Run setup.sh in bash

Summary:
#!/bin/sh can be symlinked to bash or dash but certain commands in the script are bash commands
and fail when executing in dash.
So, execute in a bash shell.

Test Plan: Actually sets up without failing.

Reviewers: spang

CC: mg

Differential Revision: https://review.inboxapp.com/D85
DB table changes to ImapAccount, Message tables.

Summary:
Move UserInfo columns from Account->ImapAccount table. Create is_created column in Message table, needed for sending mail.
Migrations + updated tests.

Test Plan:
Syncs as before.
Tests pass as before.

Reviewers: spang, mg

Differential Revision: https://review.inboxapp.com/D92
util/db.py: Defensive assert for reset_columns default values
D92 CR changes
Remove is_created column in Message table, fix alembic branches