Apply caching to speed up UI; display restricted showcase images if signed in.
- Convert direct
can?(:read, obj)
calls to use method that caches the response. - Adds method to check and cache for 5 minutes whether the public user has read ability on an object.
- Adds methods for getting image server paths without an access token.
- Uses (and then caches where possible) the image server path without a token for objects that the public user can read.
Note: There is some technical debt evident here. I've modified methods that did not already have tests. In the interest of time I've added tests for new methods I've added, but have not added tests for methods that did not already have them.