Add support for overriding audit scores

[scriptsrc]

Replaces #535
Fixes merge conflicts and db migration path.

From @kalpatel01:

Type: generic-large-feature

Why is this change necessary?
We've run into instances where we have wanted to reconfigure watcher run
intervals to improve performance or even remove watchers that were
causing problems. Currently this requires logging into the server and
physically changing the code

This change addresses the need by:
Provides a Watcher Config page in Settings and an api where a user can
configure the run interval and the active flag

Potential Side Effects:
No known side effects

[coveralls]

Changes Unknown when pulling bf1996b on Bridgewater-7923_OverrideScores into ** on develop**.

[scriptsrc]

Here's something I was confused on until Curtis/Anne cleared it up for me:
The account patterns allow you to apply an override score to multiple accounts at once. Example: Change scores to 0 for all of our PLAY accounts with one pattern. There's a note at the bottom of misc.rst that I had misinterpreted to mean that account patterns couldn't match to multiple accounts. That note actually means there could be undefined behavior if conflicting account patterns are created.

I'm going to merge this in.

I have a few ideas for the future:

• Add Tags to accounts, and allow patterns to be based on these tags. (Similar to the notes field example.)
• Make it so that account patterns can be re-used, so you don't need to recreate it for each override.
• Make the Account Value field an autocomplete. We'll need to send distinct account values to the client.
• Some UI changes so you can navigate back to /viewauditscore/<id> from /auditscore/<id>/createaccountpatternauditscore

[coveralls]

Changes Unknown when pulling bf0c9c0 on Bridgewater-7923_OverrideScores into ** on develop**.