The name AliasAndImplicationImporter is a holdover from the time before
bulk update requests existed. This was a bad name because it doesn't do
any actual importing, instead it's used for parsing and executing bulk
update requests.
Also remove non-nullable and default options from migration. The column
didn't originally have these options so they shouldn't be added if the
migration is reverted.
Remove the post update count estimate from BUR show pages. This was
complex, slow, and usually inaccurate since it assumed that requests in
a BUR had no overlap with each other, which usually wasn't the case.
Ensure dtext is always wrapped in a `<div class="prose">` or
`<span class="prose">` (for inline dtext) container so that dtext css is
properly applied.
