docs: add example to use cloudrun deployer + local build

[renzodavid9]

Fixes: #8289

Description
This PR is to show an example of how to configure a Skaffold project to use the Cloud Run deployer with a local built image. It shows how to configure the project and what important things to keep in mind for that.

[codecov]

Codecov Report

Merging #8983 (de32ce4) into main (290280e) will decrease coverage by 6.84%.
Report is 988 commits behind head on main.
The diff coverage is 49.80%.

@@            Coverage Diff             @@
##             main    #8983      +/-   ##
==========================================
- Coverage   70.48%   63.65%   -6.84%     
==========================================
  Files         515      624     +109     
  Lines       23150    31941    +8791     
==========================================
+ Hits        16317    20331    +4014     
- Misses       5776    10081    +4305     
- Partials     1057     1529     +472     

Files Changed	Coverage Δ
cmd/skaffold/app/cmd/completion.go	13.04% <0.00%> (-1.25%)	⬇️
cmd/skaffold/app/cmd/config/list.go	65.21% <ø> (ø)
cmd/skaffold/app/cmd/config/set.go	88.72% <ø> (ø)
cmd/skaffold/app/cmd/config/util.go	54.28% <ø> (ø)
cmd/skaffold/app/cmd/credits.go	100.00% <ø> (ø)
cmd/skaffold/app/cmd/credits/export.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/deploy.go	40.90% <0.00%> (-12.94%)	⬇️
cmd/skaffold/app/cmd/generate_pipeline.go	60.00% <ø> (ø)
cmd/skaffold/app/cmd/inspect_modules.go	65.00% <ø> (ø)
cmd/skaffold/app/cmd/inspect_profiles.go	66.66% <ø> (ø)
... and 40 more

... and 415 files with indirect coverage changes

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[container-tools-bot]

Error creating deployment docs-controller-deployment-8983, please visit https://storage.googleapis.com/webhook-logs/logs-8983-1691162519558662724 to view logs.