Create remote cache entries table for Maven virtual registry

Context

This MR implements the first step of repartitioning the Maven virtual registry cache by creating a new table virtual_registries_packages_maven_cache_remote_entries to replace the existing virtual_registries_packages_maven_cache_entries table.

What does this MR do and why?

• Creates the new table virtual_registries_packages_maven_cache_remote_entries with improved partitioning strategy
• Switches the partition key from the current setup to group_id
• Updates the primary key to [group_id, iid]
• Implements iid as a unique column across partitions connected to a single sequence
• Adds some basic indexes (more will follow)

References

• Maven: redo partitioning of virtual_registries_... (#583723) • Moaz Khalifa

Screenshots or screen recordings

N/A

How to set up and validate locally

Run the migration locally and in rails console you can test inserting rows into the new table:

# select or create an upstream
upstream = VirtualRegistries::Packages::Maven::Upstream.last || FactoryBot.create(:virtual_registries_packages_maven_upstream)

VirtualRegistries::Packages::Maven::Cache::Remote::Entry.create(group: upstream.group, upstream: upstream, size: 1024, relative_path: 'test/path.txt', file: 'dummy', object
_storage_key: 'dummy', file_sha1: 'abcdefghijklmnqrstuv')

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #583723