Allow to disable deployments

[qwerty287]

…but if they're enabled, allow for all events. Also add warning that you should only enable it if you trust the users with push access.

closes #3559

[woodpecker-bot]

Deployment of preview was successful: https://woodpecker-ci-woodpecker-pr-3570.surge.sh

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 35.98%. Comparing base (e1b574a) to head (819ac16).
Report is 6 commits behind head on main.

❗ Current head 819ac16 differs from pull request most recent head 430479f. Consider uploading reports for the commit 430479f to get more accurate results

Files	Patch %	Lines
server/api/pipeline.go	0.00%	5 Missing ⚠️
server/api/repo.go	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3570      +/-   ##
==========================================
- Coverage   36.00%   35.98%   -0.02%     
==========================================
  Files         231      231              
  Lines       15543    15553      +10     
==========================================
+ Hits         5596     5597       +1     
- Misses       9530     9539       +9     
  Partials      417      417              

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