Allow access using a Jenkins API token without an OIDC Session

[mikecirioli]

Proposing a new option of the OicSecurityRealm that will allow an administrator to Allow access using a Jenkins API token without an OIDC Session.

Currently, when using the oic-auth plugin, if a user explicitly logs out of the IdP then they will now longer be able to perform any sort of action using jenkins api tokens because the oic-auth plugin will reject the request due to the OicSession being null. This behavior may make sense for some users, but it can cause problems for other users who may be relying on external automation tools which make use of jenkins api tokens for authentication.

This PR introduces a new (optional, disabled by default) configuration which lets an admin re-enable the traditional jenkins api token access behavior. This is accomplished by checking to see if a request appears to be using a valid jenkins api token, and if so hands of the request processing to the next filter in the chain instead of procssessing it as an OIC based access request.

Testing done

new unit test has been added to validate the new functionality

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[codecov]

Codecov Report

Attention: Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.

Project coverage is 72.47%. Comparing base (8e99549) to head (791ef3c).
Report is 35 commits behind head on master.

Files with missing lines	Patch %	Lines
...va/org/jenkinsci/plugins/oic/OicSecurityRealm.java	81.81%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #386      +/-   ##
============================================
+ Coverage     71.44%   72.47%   +1.03%     
- Complexity      232      244      +12     
============================================
  Files            11       12       +1     
  Lines           991     1021      +30     
  Branches        142      148       +6     
============================================
+ Hits            708      740      +32     
+ Misses          205      201       -4     
- Partials         78       80       +2     

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[amuniz]

Looks good to me (needs spotless fixes).

[mikecirioli]

I plan to merge this at the end of the day today unless anyone has an objection

cc: @jenkinsci/oic-auth-plugin-developers