Define and implement secret querier via func interface to let pipeline compiler secrets

[6543]

Address #4378

• this only sends secrets used to the agent
• allow for future improvement to inject a secret-querier that query an secret backend directly

[woodpecker-bot]

Deployment of preview was torn down

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 67.27273% with 18 lines in your changes missing coverage. Please review.

Project coverage is 27.47%. Comparing base (5699d22) to head (ed90798). Report is 22 commits behind head on main.

Files with missing lines	Patch %	Lines
cli/exec/exec.go	0.00%	12 Missing :warning:
pipeline/frontend/yaml/compiler/compiler.go	40.00%	2 Missing and 1 partial :warning:
server/pipeline/stepbuilder/stepBuilder.go	90.00%	1 Missing and 1 partial :warning:
agent/logger.go	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #4380 +/- ## ========================================== + Coverage 27.37% 27.47% +0.09% ========================================== Files 380 380 Lines 27794 27800 +6 ========================================== + Hits 7608 7637 +29 + Misses 19501 19478 -23 Partials 685 685 ```

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[6543]

-> this destryes the usage of secrets to only maks the log of certain output ...

I'll worke on an other method to not have to send all secrets to the agent

[6543]

-> https://github.com/woodpecker-ci/woodpecker/pull/4384