Action checkstyle

[N0W0RK]

Structure changes in .github.

Added GithubAction for CI using checkstyle with the Artemis configuration (closes #38)

[JohannesStoehr]

Believe me, you want to leave out <module name="MagicNumber"/>.
Otherwise you will have a hard time writing the tests

[CrsiX]

Based on GitHub Docs the issue and PR template files may not be recognized correctly. For example, valid path names for the PR template seem to be:

• /pull_request_template.md
• /docs/pull_request_template.md
• /.github/pull_request_template.md
• /.github/PULL_REQUEST_TEMPLATE/*

I think we should redo the renaming of the template files.

[CrsiX]

I will add some more changes based on this document and I would really appreciate if you comment on them later on again, too. This way, we come to a solution together :)

[CrsiX]

Looks like we will have a lot of cleaning work to do if we really want to get a 'good' code base. Reviewdog reports:

Filtered Findings (11973)

[CrsiX]

We should also discuss about the setting of the fail_on_error value. Currently, it's false (default), meaning the tests will always pass with a ✔️ even if errors have been found. Otherwise (true), they would fail with a ❌ sign.
And finally, we could also add a badge to our README to show all users looking at the GitHub page that we have java style checkers in place (and they actually reported tons of style errors) ...

[JohannesStoehr]

Looks like we will have a lot of cleaning work to do if we really want to get a 'good' code base. Reviewdog reports:

Filtered Findings (11973)

:monkaGiga:
But a lot of errors seem to come from too long lines. Maybe running a linter once over every file would already fix a lot of these reported errors?

[N0W0RK]

First of all sory for fucking up the template location and configuration.

As far as I care, at least the line length case can be, either commented out or removed completely. We are creating sometimes large arrays with specific values as test algortithms would present a solution.

Failing on Error sounds like a good idea. Having Tests that dont compile does not sound reasonable to me.

We might also unify the names for the actions. I think there are 2/3 different names in the config.

[CrsiX]

I would be fine with this settings now. Fine grained tuning can be done later on, too. Any other suggestions or comments on that? @N0W0RK