Cleanup static files and templates

"terminate with extreme prejudice"

**`/static`**
- [x] move app-specific static files to `appfolder/static/appname`
- [x] separate bootstrap files into `css/` `fonts/` and `js/`
- [x] delete `jquery/`?
- [x] update `absent_trainee_roster` to not use `django-select2`
- [x] use minified js/css and `.map` files for debugging

**`/templates`**
- [x] `/admin/absent_trainee_roster` ?
- [x] `/lifestudies`