feat: increase max_length for api tokens

[mdtro]

In support of getsentry/rfcs#32.

API Tokens will be prefixed with seven extra characters (ex. sntryu_). Eventually these plaintext token columns will be dropped, but to maintain backwards compatibility and a smooth transition to fully hashed tokens we'll still want to store them here.

[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/hybridcloud/migrations/0012_apitoken_increase_token_length.py src/sentry/migrations/0655_apitoken_increase_token_length.py ()

--
-- Alter field refresh_token on apitoken
--
ALTER TABLE "sentry_apitoken" ALTER COLUMN "refresh_token" TYPE varchar(71);
--
-- Alter field token on apitoken
--
ALTER TABLE "sentry_apitoken" ALTER COLUMN "token" TYPE varchar(71);

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.21%. Comparing base (8190a27) to head (98b8376).

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #65743       +/-   ##
===========================================
+ Coverage   58.51%   84.21%   +25.69%     
===========================================
  Files        5086     5274      +188     
  Lines      224231   235949    +11718     
  Branches    38792    40859     +2067     
===========================================
+ Hits       131206   198695    +67489     
+ Misses      92801    37035    -55766     
+ Partials      224      219        -5     

Files	Coverage Δ
.../migrations/0012_apitoken_increase_token_length.py	100.00% <100.00%> (ø)
src/sentry/hybridcloud/models/apitokenreplica.py	97.43% <100.00%> (+20.51%)	⬆️
src/sentry/models/apitoken.py	100.00% <100.00%> (+25.45%)	⬆️

... and 1920 files with indirect coverage changes