add regex replace support to ClaimTemplate

[LeoQuote]

Add regex replace support in claim template, introducing more possibility to claims, like extract repo and org name from it

fix #34

This could be a good supplement for #6 , allowing users to replace and recreate claims using existing environments.

Known issues, I'm still figuring out how to fix:

• [x] 1. I dont know what should I do to make regex optional, since the signature of the ClaimTemplate Constructor is fixed and cannot create a second constructor
• [x] 2. The default value did not show in the settings box.

Any suggestions are welcomed!

Testing done

• unit test has been added
• tried using the plugin in my jenkins

it can replace the claim correctly, presenting jwt like

{
  "iss": "https://sa-jenkins.intra.xxx.com/oidc",
  "exp": 1703501635,
  "iat": 1703498035,
  "sub": "https://sa-jenkins.intra.xxx.com/",
  "build_number": 5,
  "org": "SA",
  "repo": "opa-policies"
}

it can fulfill my requirements.

Submitter checklist

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

[LeoQuote]

this feature make it possible for the handler to know this pr is from a pull request or not

[pserranoa]

+1 good feature to manage authentication with bakends