Speed up woodpecker pipelines

[anbraten]

The pipelines executed for PRs in this repo could be improved to save resources and speed up:

• use more path filters
• only push images if requested for a PR (could be done by adding a label to the PR)
• only run build for amd64 architecture as cross-compiling is pretty slow
• ...

[qwerty287]

What do you think about skipping test and web pipelines on master pushes/merging PRs? They only contain linters and test and since almost everything is done via PRs the code should be checked by them already when a commit is pushed to the PR.

[anbraten]

Yeah sounds fine to me

[6543]

did some bits at #1966

[qwerty287]

We did most for this:

• path filters for most steps
• docker pushes only with label
• only deploying, image pushing and codecov on pushes
• reduced archs for PRs

[anbraten]

last thing I can image would be #2295