Make token type case insenstive when creating serv / dev tokens

[MrCreosote]

Also clarify MFAStatus.UNKNOWN docs

Fixes #441

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.41%. Comparing base (2b7fc4b) to head (3000b4a).
⚠️ Report is 5 commits behind head on develop.

Additional details and impacted files

@@            Coverage Diff             @@
##             develop     #501   +/-   ##
==========================================
  Coverage      93.41%   93.41%           
- Complexity      2166     2167    +1     
==========================================
  Files            129      129           
  Lines           7625     7626    +1     
  Branches        1180     1181    +1     
==========================================
+ Hits            7123     7124    +1     
  Misses           459      459           
  Partials          43       43           

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