New Feature: Support for logo on right hand side & associated Search bar location.

This is our last real hack of Adaptable compared to master to comply with UCL's branding guidelines of having logo on the right handside and just touching the line.

While I didn't think much about getting this upstream as it's very specific to UCL branding, I am wondering wether we should have the general left / right option for the logo. This would be relevant for us when it comes time for us look at enabling Global Search where we will want the search box to NOT be on top of the logo. I say that but last I checked (many years back) Adaptable had a search bar for the course search but not for use with Global Search, so that would be a prerequisite.

This is roughly our hack - could be an old version which doesn't merge cleanly - aspark21snow/moodle-theme_adaptable@349eeedb

If you think this is a lot of work let me know.