chore(workflows): customizable workflows

[Gustl22]

Description

• ability to trigger each job individually via workflow_dispatch
• categorize reusable workflows / jobs into build and test
• split trigger into pull-request and release

Checklist

• The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs:, chore: etc).
• I have read the Contributor Guide and followed the process outlined for submitting PRs.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation and added dartdoc comments with ///, where necessary.
• I have updated/added relevant examples in example.

Breaking Change

• Yes, this is a breaking change.
• No, this is not a breaking change.

Related Issues

#1333

[Gustl22]

For this to work correctly we have to change protection rules to allow merging, when pull_request workflow passed, and not anymore the build workflow.
https://github.com/orgs/community/discussions/26698#discussioncomment-3252954
build and test are reusable now, and can be called by its trigger workflow pull-request or release, which makes more sense in terms of naming.

[luanpotter]

@Gustl22 done!

[luanpotter]

LGTM

[Gustl22]

Thank you!!