Collect catalog bundles instead of compiling them

What does this MR do and why?

Replaces compiled (flattened) catalog bundles with collected ones: each component's files are stored as authored. Nothing calls these services yet; wiring into publishing comes in a follow-up MR.

• Gitlab::Ci::Catalog::Bundle::Format dumps bundle format version 1 as JSON, keeping the collected YAML as opaque strings so files round-trip byte for byte
• Ci::Catalog::Resources::Bundle::CollectService replaces CompileService, returning one bundle per component or every rejection prefixed with its component name
• Ci::Catalog::BundledResources::CollectAndStoreService (renamed from CompileAndStoreService) stores the bundles, rejects non-public projects because any project on a Cell can read a bundle, and does nothing for an already collected version
• CollectAndStoreService#prepare and #persist are public, so publishing can upload before its transaction and write the rows inside it
• Bundle::ObjectKey names objects <component>.json, uploaded as application/json
• Removes Bundle::Compiler, CompileService and their specs, since collection supersedes them

References

• Related to #630810 (closed)
• Previous MR, which added Bundle::Collector: !259106 (merged)

How to set up and validate locally

1. bundle exec rspec spec/lib/gitlab/ci/catalog/bundle/format_spec.rb spec/services/ci/catalog/resources/bundle/collect_service_spec.rb spec/services/ci/catalog/bundled_resources/collect_and_store_service_spec.rb spec/lib/gitlab/ci/catalog/bundle/object_key_spec.rb spec/uploaders/ci/catalog/bundled_resources/component_uploader_spec.rb

MR acceptance checklist

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