/recent-changes log should list and link to post

[jf1]

Current column: Candidate edited contains a person or is blank. C/should be: Candidate or post edited then list and link to a post whenever a post-level action is being logged.

[jf1]

Logging of post-level actions was first raised in #884 however that issue didn't cover how this information should be displayed.

The handling of results is similar to that for constituency-lock changes detailed above.

For a record-council-result action there's no link to the post or its results page in the entries on the /recent-changes page:

The homepage's "Recent changes" section does have a link to the result:

However there's an error here for County Council CEDs. The link for Wallingford still uses the now-depreciated unit_id: prefix which should be replaced with the new CED: prefix, ie: Wallingford.