Expose and encourage use of canuselocalstore in MUC config

The ability for certain cache stores to be local to each front end, ie canuselocalstore = true, has potentially massive performance gains (eg just moving lang strings alone to local can be a big boost). But this is a fairly hidden feature, you can only see this in the cache admin gui when you drill down into each cache store item.

I'd like to see whether this is true or false for all cache definitions up front on the master muc admin page so you can make sure they are all mapped to local caches where possible.

Also there is zero moodle dev docs for people implementing cache definitions to allow them to take advantage of this correctly.

https://docs.moodle.org/dev/Cache_API