Support fetching versioned README for CI Catalog resource in GraphQl

What does this MR do and why?

Background context:

A Catalog Resource is a project that can have multiple Versions. A Version is equivalent to the project's Release. The Version's name identifier is equivalent to the Release's tag. So given a Version's name, we should be able to retrieve the README blob from the corresponding commit.

This MR:

This MR adds fields to GraphQl so that we can fetch the versioned README content from the ciCatalogResource(s) endpoints. Specifically, it:

• Adds the name filter argument to VersionsResolver.
• Updates VersionsFinder so that it can filter by version name.
• Adds the readme_html field to VersionType.

Resolves #429279 (closed).

How to set up and validate locally

1. Create a published catalog resource. You can seed one quickly by running the following command in your gitlab directory:

bundle exec rake "gitlab:seed:ci_catalog_resources[<YOUR-GROUP-PATH>, 1, true]"

2. In your catalog resource project, update the README.md content with ## Version 1 and commit the change to branch1. Then update the README.md content with ## Version 2 and commit the change to branch2.

3. Create tags for the branches, named tag1 and tag2 respectively. Then create a release for each tag. The release for tag2 should have a later date than tag1.

4. Go to http://gdk.test:3000/-/graphql-explorer and test the following query. Update the path variable as needed.

query getCiCatalogResourceReadme($fullPath: ID!, $version: String) {
  ciCatalogResource(fullPath: $fullPath) {
    id
    name
    versions(name: $version) {
      nodes {
        id
        name
        releasedAt
        readmeHtml
      }
    }
  }
}

{ "fullPath": "group-a/ci_seed_resource_0", "version": "tag1" }

Observe that the README content returned corresponds to the given version name.

5. Test the following query and confirm that the README content outputted is of the latest version (i.e. "Version 2").

query getCiCatalogResourceReadme($fullPath: ID!) {
  ciCatalogResource(fullPath: $fullPath) {
    id
    name
    latestVersion {
      id
      name
      releasedAt
      readmeHtml
    }
  }
}

{ "fullPath": "group-a/ci_seed_resource_0" }

Query plan

We may improve this query in the future by removing the need to JOIN with releases in #436410 (closed).

SELECT "catalog_resource_versions".*
FROM "catalog_resource_versions"
INNER JOIN "releases" ON "releases"."id" = "catalog_resource_versions"."release_id"
WHERE "catalog_resource_versions"."catalog_resource_id" = 1
AND "releases"."tag" = 'tag1'

Query plan link: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/25057/commands/79592

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #429279 (closed)