feat(config): support remote blob storage for service configuration

[erka]

closes #2862

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 14 lines in your changes are missing coverage. Please review.

Project coverage is 72.32%. Comparing base (f997fb9) to head (2ecbd02).
Report is 230 commits behind head on main.

Files	Patch %	Lines
internal/config/config.go	62.50%	6 Missing and 6 partials ⚠️
internal/storage/fs/object/mux.go	91.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2983      +/-   ##
==========================================
+ Coverage   70.78%   72.32%   +1.54%     
==========================================
  Files          91       95       +4     
  Lines        8729     7217    -1512     
==========================================
- Hits         6179     5220     -959     
+ Misses       2165     1602     -563     
- Partials      385      395      +10     

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[markphelps]

tested it out locally with minio, works great!! thanks @erka. amazing work as always

one minor comment about test name

FYI this is how I tested:

1. installed minio via homebrew
2. ran minio server: MINIO_ACCESS_KEY=admin MINIO_SECRET_KEY=password minio server ~/minio
3. Logged in to minio UI with admin/password at http://localhost:59134
4. Created bucket flipt
5. Uploaded default config AFTER changing the GRPC server port to 9001 as it conflicts with minio default port
6. Ran Flipt with AWS_ACCESS_KEY=admin AWS_SECRET_ACCESS_KEY=password ./bin/flipt --config="s3://flipt/config.yml?region=minio&endpoint=http://localhost:9000"