Purge web directory and everything HTML, refs T985

Summary:
- remove `web/`
- remove npm, bower, and bundle files
- reduce all exceptions to JSON
- purge HTML stuff (layouts, etc)

Test Plan:
```
bin/update
bin/behat --config application/tests/behat.yml -f progress
```

Reviewers: vladimir, aMoniker

Reviewed By: aMoniker

Subscribers: spaudanjo, srutto, rjmackay

Maniphest Tasks: T985

Differential Revision: https://phabricator.ushahidi.com/D457