feat: Add robots.txt and sitemap.xml (DEV-3931)

[seakayone]

• Add robots.txt and sitemap.xml
• refactor: Align module structure with api
• make snackbar easier on the eyes with fading in and out a bit slower
• module naming
• fmt

[linear]

DEV-3931 Add robots.txt and sitemap.xml

[codecov]

Codecov Report

Attention: Patch coverage is 20.00000% with 32 lines in your changes missing coverage. Please review.

Project coverage is 61.3%. Comparing base (9e68387) to head (0ff0abb).

Additional details and impacted files

Files	Coverage Δ
dsp-meta/src/api/handler/health.rs	100.0% <100.0%> (ø)
dsp-meta/src/api/handler/v1/projects/handlers.rs	0.0% <ø> (ø)
dsp-meta/src/api/handler/v1/projects/responses.rs	0.0% <ø> (ø)
dsp-meta/src/api/router.rs	99.1% <100.0%> (+<0.1%)	⬆️
dsp-meta/src/domain/service/repository_contract.rs	0.0% <ø> (ø)
dsp-meta/src/api/handler/sitemap_xml.rs	0.0% <0.0%> (ø)
...eta/src/domain/service/project_metadata_service.rs	36.3% <0.0%> (-13.7%)	⬇️
dsp-meta-cmd/src/main-server.rs	0.0% <0.0%> (ø)
...ta/src/repo/service/project_metadata_repository.rs	61.4% <0.0%> (-6.0%)	⬇️
dsp-meta/src/api/handler/robots_txt.rs	0.0% <0.0%> (ø)