Refactor logging to have consistent Loki labels

[nullfunc]

Organize loki labels across our codebase to have consistent categorization.

1. Create a document to detail the current labels
2. Document the desired categorization
3. Implement across code base

Example: Rectify issues like tracking service state changes. At current service deployment is via fabric logs while for service destruction state is tracked via the cd logs.

[lionello]

This would fix #420

[lionello]

Examples, https://github.com/DefangLabs/defang-mvp/blob/5ddb064cfcdf218a14caa7b004bba568ac063d24/fabric/cmd/server/fabric.go#L646 https://github.com/DefangLabs/defang-mvp/blob/e4e49fefc0e050da4dece1273cf76e95fda5e041/fabric/cmd/server/fabric_utils.go#L82 https://github.com/DefangLabs/defang-mvp/blob/f44705a430aac7c0a986fa1ba171322b18e64da8/fabric/cmd/server/fabric_grpc.go#L802 https://github.com/DefangLabs/defang-mvp/blob/5ddb064cfcdf218a14caa7b004bba568ac063d24/fabric/cmd/server/fabric.go#L684