Add custom function support

[seratch]

This pull request adds remote function support, which is still in beta, to this SDK. Sorry, the duplicated PRs (due to my operation error) are confusing but this is the final version of #1239

Developers can implement a remote function and its interactivity this way:

// app.event(FunctionExecutedEvent.class, (req, ctx) -> {
// app.function("hello", (req, ctx) -> {
app.function(Pattern.compile("^he.+$"), (req, ctx) -> {
  ctx.logger.info("req: {}", req);
  ctx.client().chatPostMessage(r -> r
    .channel(req.getEvent().getInputs().get("user_id").asString())
    .text("hey!")
    .blocks(asBlocks(actions(a -> a.blockId("b").elements(asElements(
      button(b -> b.actionId("remote-function-button-success").value("clicked").text(plainText("block_actions success"))),
      button(b -> b.actionId("remote-function-button-error").value("clicked").text(plainText("block_actions error"))),
      button(b -> b.actionId("remote-function-modal").value("clicked").text(plainText("modal view")))
    )))))
  );
  return ctx.ack();
});

app.blockAction("remote-function-button-success", (req, ctx) -> {
  Map<String, Object> outputs = new HashMap<>();
  outputs.put("user_id", req.getPayload().getFunctionData().getInputs().get("user_id").asString());
  ctx.client().functionsCompleteSuccess(r -> r
    .functionExecutionId(req.getPayload().getFunctionData().getExecutionId())
    .outputs(outputs)
  );
  ctx.client().chatUpdate(r -> r
    .channel(req.getPayload().getContainer().getChannelId())
    .ts(req.getPayload().getContainer().getMessageTs())
    .text("Thank you!")
  );
  return ctx.ack();
});
app.blockAction("remote-function-button-error", (req, ctx) -> {
  ctx.client().functionsCompleteError(r -> r
    .functionExecutionId(req.getPayload().getFunctionData().getExecutionId())
    .error("test error!")
  );
  ctx.client().chatUpdate(r -> r
    .channel(req.getPayload().getContainer().getChannelId())
    .ts(req.getPayload().getContainer().getMessageTs())
    .text("Thank you!")
  );
  return ctx.ack();
});
app.blockAction("remote-function-modal", (req, ctx) -> {
  ctx.client().viewsOpen(r -> r
    .triggerId(req.getPayload().getInteractivity().getInteractivityPointer())
    .view(view(v -> v
      .type("modal")
      .callbackId("remote-function-view")
      .title(viewTitle(vt -> vt.type("plain_text").text("Remote Function test")))
      .close(viewClose(vc -> vc.type("plain_text").text("Close")))
      .submit(viewSubmit(vs -> vs.type("plain_text").text("Submit")))
      .notifyOnClose(true)
      .blocks(asBlocks(input(input -> input
        .blockId("text-block")
        .element(plainTextInput(pti -> pti.actionId("text-action").multiline(true)))
        .label(plainText(pt -> pt.text("Text").emoji(true)))
      )))
    )));
  ctx.client().chatUpdate(r -> r
    .channel(req.getPayload().getContainer().getChannelId())
    .ts(req.getPayload().getContainer().getMessageTs())
    .text("Thank you!")
  );
  return ctx.ack();
});

app.viewSubmission("remote-function-view", (req, ctx) -> {
  Map<String, Object> outputs = new HashMap<>();
  outputs.put("user_id", ctx.getRequestUserId());
  ctx.client().functionsCompleteSuccess(r -> r
    .functionExecutionId(req.getPayload().getFunctionData().getExecutionId())
    .outputs(outputs)
  );
  return ctx.ack();
});
app.viewClosed("remote-function-view", (req, ctx) -> {
  Map<String, Object> outputs = new HashMap<>();
  outputs.put("user_id", ctx.getRequestUserId());
  ctx.client().functionsCompleteSuccess(r -> r
    .functionExecutionId(req.getPayload().getFunctionData().getExecutionId())
    .outputs(outputs)
  );
  return ctx.ack();
});

References:

• Add remote function support bolt-python#986

Category (place an x in each of the [ ])

• bolt (Bolt for Java)
• bolt-{sub modules} (Bolt for Java - optional modules)
• slack-api-client (Slack API Clients)
• slack-api-model (Slack API Data Models)
• slack-api-*-kotlin-extension (Kotlin Extensions for Slack API Clients)
• slack-app-backend (The primitive layer of Bolt for Java)

Requirements

Please read the Contributing guidelines and Code of Conduct before creating this issue or pull request. By submitting, you agree to those rules.

[codecov]

Codecov Report

Attention: Patch coverage is 71.73913% with 13 lines in your changes are missing coverage. Please review.

Project coverage is 74.83%. Comparing base (a9a3599) to head (5b294c1).

❗ Current head 5b294c1 differs from pull request most recent head 0f27992. Consider uploading reports for the commit 0f27992 to get more accurate results

Files	Patch %	Lines
bolt/src/main/java/com/slack/api/bolt/App.java	57.14%	2 Missing and 4 partials ⚠️
...m/slack/api/bolt/request/builtin/EventRequest.java	57.14%	0 Missing and 3 partials ⚠️
...ck/api/bolt/request/builtin/ViewClosedRequest.java	33.33%	1 Missing and 1 partial ⚠️
.../main/java/com/slack/api/bolt/context/Context.java	83.33%	0 Missing and 1 partial ⚠️
...k/api/bolt/request/builtin/BlockActionRequest.java	85.71%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1241      +/-   ##
============================================
- Coverage     74.84%   74.83%   -0.02%     
- Complexity     4128     4141      +13     
============================================
  Files           443      444       +1     
  Lines         12786    12830      +44     
  Branches       1319     1330      +11     
============================================
+ Hits           9570     9601      +31     
- Misses         2452     2455       +3     
- Partials        764      774      +10     

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[WilliamBergamin]

LGTM 💯

[WilliamBergamin]

Looks good 💯