This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
We were looking up each mention one by one without any form of caching and that results
in a problem somewhat similar to an N+1. When we have to do alot of DB
lookups, it also increased the time spent in the V8 context which may
eventually lead to a timeout. The change here makes it such that mention lookups only does a single
DB query per post that happens outside of the V8 context.
* Adds primary user group as a class to quote
This feature addition will add the class `group-PRIMARY_USER_GROUP` to
the quote `aside`. `PRIMARY_USER_GROUP` will be the primary user group
of the user being quoted. This is similar to the class that is added to
a `topic-post`.
* Remove trailing whitespace
* Fix avatar in test
* Address PR comments
* Fix trailing whitespace
