Update review pages

Show the same options for reviews on the dashboard and on review screens.
Add title to all pages within the review section.

Improve proposal/review styling

Use correct block for page titles. Fix element styles to be consistent
across site. Use fluid layout for review to enable sidebar.

Don't try to initialise dataTable twice

Old code was initialising the dataTable twice - once in the parent
block and once in the child. This doesn't actually work and just
caused errors.

Switch to only initializing it once. Unfortunately this creates
copy-pasta :(

Supply a default value for target_audience for the ART+TECH miniconf

* The base model requires a value here
* But we aren't using one; so there's none on the form
* This change supplies a custom enumeration that's specific for this
particular model, which has one value, which is a default value,
which simply says that the field is N/A
* This does mean that when viewing or reviewing the proposal one sees
the Target Audience field, but it will say N/A.

* Testing has shown that this does not affect the other types which
descend from the base Proposal class; they still use the default
enumeration.

Set review-table class to get goodness on notification page

Flagging this as a review table means we get sorting, pagination, and
search. Much awesome, esp when we want to do this like "show me all
the ones that haven't been notified yet"

Bootstrapification

Boot custom CSS, and put some base, standard css in its place.
Shame I did not start with fresh Bootstrap4, but oh well.

Some more templates could be made to make this less messy, which would
be good.