Token api tidy up

[knolleary]

Part of https://github.com/FlowFuse/security/issues/84

Whilst reviewing token apis (PAT/HTTP/Provisioning), I found some inconsistencies with our design guidelines for APIs.

This PR tidies up the related APIs and adds additional test coverage for the affected routes.

[codecov]

Codecov Report

Attention: Patch coverage is 89.77273% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 41.86%. Comparing base (70f518f) to head (286cd3a).

Files	Patch %	Lines
forge/db/controllers/AccessToken.js	88.88%	2 Missing ⚠️
forge/db/views/AccessToken.js	87.50%	2 Missing ⚠️
frontend/src/pages/account/Security/Tokens.vue	0.00%	2 Missing ⚠️
frontend/src/pages/instance/Settings/Security.vue	0.00%	2 Missing ⚠️
forge/ee/routes/httpTokens/index.js	94.44%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3717      +/-   ##
==========================================
+ Coverage   41.72%   41.86%   +0.14%     
==========================================
  Files         631      631              
  Lines       24533    24541       +8     
  Branches     6012     5998      -14     
==========================================
+ Hits        10236    10274      +38     
+ Misses      14297    14267      -30     

Flag	Coverage Δ
backend	78.88% <94.04%> (+0.22%)	⬆️
frontend	1.90% <0.00%> (-0.01%)	⬇️

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