Add pagination support for FindAllTagsRequest

Problem

Tags endpoint performance is inefficient for projects with many tags. We fetch all project tags and only after we apply pagination.

Proposal

• Add Gitaly pagination support for FindAllTagsRequest gitaly!3861 (merged) (done)
• Update GitalyClient::RefService to handle pagination parameters - !70199 (merged) (in progress)
• Extend TagsFinder and Tags API to use Gitaly based pagination.