Lots of layout things

Not everything that I wanted to finish is done, but I wanted to make a PR to merge some things in so:
 a) people know what fragments already exist in terms of navigation, so we can avoid some redundancy
 b) reduce # of merge conflicts omg

Things I did:
- merged AccountRegistration and EventRegistration together.  I feel like there is enough space to do this without being overwhelming, and since we're only pushing data to Salesforce at the end, this seems okay now.
- created assets and made custom EditText, Spinners, Checkboxes, etc.
- Sidebar buttons now work and will move to the correct fragment in the backstack if possible
- created fragments for Selection, Search and SearchResults, and created appropriate assets

It still doesn't really look the way it's supposed to, but eh, its getting there.
Lmk if we implement this later because currently it is an unused import