feature: Allow listing of acct

[VivienGiraud]

This PR add usage of listing accounts given an app name.

>>> keyring list MyApp
['GitHub', 'Microsoft']

Then you will be able to access an specific account using:

>>> keyring get MyApp Microsoft
MY_PASSWORD

[VivienGiraud]

Hi @mitya57 ,
Can you tell me if you could review this feature?
I working on an open source project that will rely on this functionality.
Have a pleasant day.

[mitya57]

1. I would name the function list_passwords (in plural), not list_password.
2. Ideally we need support in all backends, not just in the macOS one.
3. The CI is failing. In particular, you forgot to import your function in keyring/cli.py.

Note: I'm not the chief maintainer of Keyring, @jaraco is, so he has the final word.

[jaraco]

Overall, this looks good. I have a couple of comments about naming and the design.

I'm also curious - what should this project think about the unimplemented backends? Ideally, a feature like this would be launched with support in Mac, Windows, and Linux. Would you be willing to explore an implementation that works in those backends?

Finally, this change should demand some tests. Let's make sure the test suite exercises this new expectation and functionality.

[jaraco]

How about name it list_accounts or list_users, since "username" and "account" are the terms used for these fields and "passwords" aren't involved in the result.

[jaraco]

Probably this should mention "system" and not "app_name", because "system" is what's mentioned above.

[jaraco]

We should think carefully about the "command" here. It's called "list", but "list" could mean "list users" or "list systems" or "list users and systems". I wonder if we shouldn't instead allow a generic "list" that takes a string and matches any system:password where that string is found. Let's take some time to think about other use-cases other than exact matches of a system.