Summary:
Ref T12819. Ferret currently does substring search, but this is not the default mode users expect: when you search for the "RICO" act, you do not expect to find documents containing "apRICOt" even though "RICO" is a substring.
To support term search, index the corpus as a list of terms with puncutation removed and whitespace normalized so the engine can match against it.
Test Plan:
Ran `storage upgrade`, ran `search index`, saw sensible database results:
```
rawCorpus: This is the task description.
Hark! Whom'st'dve eaten this "food" shall surely ~perish~?? #blessed
normalCorpus: thi the task descript hark whom dve eaten food shall sure perish bless
termCorpus: This is the task description Hark Whom'st'dve eaten this food shall surely perish blessed
```
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T12819
Differential Revision: https://secure.phabricator.com/D18498
