Rewrite project versions cache

Rewrite version_get_all_rows so it doesn't perform db queries and rely
in version_cache_array_rows.

Rewrite version_cache_array_rowsto clean up code and improve caching
for non existant projects (eg, ALL_PROJECTS), or projects with no
versions.

Both changes fixes

• A recurrent cache miss when ALL_PROJECT was part of the inheritance
  projects scope in a query for versions for a project.
• A potentially wrong cached response for project versions (see 0024821).

Fixes: 0023245, 0024821