Warn users for bad-habits and deprecations in configs

[6543]

I think woodpecker should ignore errors etc while cli lint should warn you if your config do have strange things ...

• conditions that will never be true
• filters that will never apply (event: tag & branch: main -> branch is ignored in all cases)
• ...

Originally posted by @6543 in #921 (comment)

[anbraten]

Yeah we really need to give some love to the cli especially the lint and exec commands.

In general I would prefer to be as strict as possible with linting via cli and the server itself and at least be equal in both systems as that solves a lot of headache especially to new users like why is it throwing an error / showing a warning in the cli, but the server doesn't even care about it ...

[x80486]

There could be also a UI to accomplish this. A user just paste the pipeline definition and it will tell if there is anything wrong. In subsequent releases could be polished to say exactly where the problem is — if not supported by the CLI.