admin:repo_hook mention in help

handle exceptions of extensions

…t null

will be useful in repository name

caused by self-test validation for custom hook url

fix "Unknown content type null" in logs and since for 1.12.0 api

See JENKINS-29794 for details.

[JENKINS-29787] Fix NPE for race condition(?).

instead of own plain token usage

- with credentials usage
- with migrator from old gh-push-trigger descriptor config options to new gh-plugin
- with bean class to store deprecated creds (used only for migration)

+ reformat some code
+ add getters for fields

…repo-name

cleanup all gh-push-trigger descriptor related lines

- for migration process
- for changes in hooks
- for configuration logic

- change dontManageHooks=false to manageHooks=true

…nced

also fix some phrases in javadocs and help

also don't bother signature validation if no header from github with signature

[JENKINS-33974] Payload verification using shared secrets

[JENKINS-37481] Ignore sign header if sign not defined in Jenkins

Allow for commit status backref configuration

* [FIXED JENKINS-38347] Use Initializer levels.

- migrator: Don't throw NPE because Descriptor wasn't ready.
- aliases: user annotation initializer.

* Ensure execution order.

Signed-off-by: Kanstantsin Shautsou <kanstantsin.sha@gmail.com>

* Move to javadoc

…ource

https://issues.jenkins-ci.org/browse/JENKINS-38665

Signed-off-by: Kanstantsin Shautsou <kanstantsin.sha@gmail.com>