Fixes #37989 - More APIs and remote repository mirroring action

[sjha4]

What are the changes introduced in this pull request?

Add API endpoints for remote repositories, manifests and introduce the remote repository mirroring action which mirrors the remote repository into a katello repository.

Considerations taken when implementing this change?

Added a registry_url on remote object cause remote url != registry URL.

What are the testing steps for this pull request?

Run bundle exec rails db:migrate to migrate db
Run following to create 2 remotes, one pointing to redhat flatpak index and another at fedora flatpak index:

remote1 = Katello::FlatpakRemote.new(name: "Redhat flatpak", 
url: "https://flatpaks.redhat.io/rhel",
organization_id: 1,
seeded: true,
username: get from [token.redhat.com ](https://access.redhat.com/terms-based-registry/token/)
token: get from [token.redhat.com ](https://access.redhat.com/terms-based-registry/token/)
)
remote1.save!

remote2 = Katello::FlatpakRemote.new(name: "Fedora flatpak", url: "https://registry.fedoraproject.org/",organization_id: 1,seeded: true)
remote2.save!

Run the below actions to scan the 2 indexes and you should have 2 successful actions in your foreman tasks.

#Sync redhat flatpak:
redhat_remote = Katello::FlatpakRemote.find_by(name: "Redhat flatpak")
ForemanTasks.sync_task(::Actions::Katello::Flatpak::ScanRemote, redhat_remote)

#Sync fedora flatpak:
fedora_remote = Katello::FlatpakRemote.find_by(name: "Fedora flatpak")
ForemanTasks.sync_task(::Actions::Katello::Flatpak::ScanRemote, fedora_remote)

API:
Remotes:
https://centos9-katello-devel.sajha.example.com/katello/api/v2/flatpak_remotes/

Remote repository:
https://centos9-katello-devel.sajha.example.com/katello/api/v2/flatpak_remotes/5/flatpak_remote_repositories/

Remote repository with manifests:
https://centos9-katello-devel.sajha.example.com/katello/api/v2/flatpak_remotes/5/flatpak_remote_repositories/1059?manifests=true

Now you can mirror the repo into Katello by providing remote repo id and a product id:
To mirror a remote repository:
Console:

product = Katello::Product.custom.last
firefox_repository = Katello::FlatpakRemoteRepository.find_by(name: "rhel9/firefox-flatpak")
ForemanTasks.sync_task(::Actions::Katello::Flatpak::MirrorRemoteRepository, firefox_repository, product)

Now sync the new repo and verify that everything looks sane.

Testing permissions:
All of the above steps should work for the admin user and the console admin.
If you create a new user role, they'll need flatpak_remote_permissions : view_flatpak_remotes, create_flatpak_remotes and edit_flatpak_remotes to do actions on remotes.
To mirror remote repos, i.e, create katello repos from remote repo, you need to have the edit_product permission.