GetRegistry should not reconfigure registry on every call

[elezar]

See moby/moby#45134 (comment) and moby/moby#45134 (comment)

[github-actions]

This issue is stale because it has been open 90 days with no activity. This issue will be closed in 30 days unless new comments are made or the stale label is removed.

[elezar]

@klihub I think this has been addressed by your most recent refactoring changes from #192

Please close this if this is the case.

[klihub]

@klihub I think this has been addressed by your most recent refactoring changes from #192

Please close this if this is the case.

With those changes in place, GetRegistry() is now a GetDefaultCache() + and optional call to Cache.Configure() on the default cache instance. It only ends up calling Configure() if there are options passed to it. It is not smart about the options themselves, though. If you call it twice in a row with the same options, it will call Configure() both times. But this should be good enough to address the main complains in the above linked moby PRs. So closing this.