[Hacktoberfest] Migrate docs to jenkinsci repo

[Dan-Heath]

This PR migrates the Job and Stage Monitoring plugin documentation from the plugins-wiki-docs repo to the github-autostatus-plugin repo as part of the Hacktoberfest docs-to-code project. It includes the following changes:

• Merged the wiki documentation with the existing Readme documentation
• Migrated the version history from the wiki and copied it to a new CHANGELOG.md file
• Updated the pom.xml file with the new documentation URL
• Changed instances of "master" to "controller" per the terminology initiative
• Performed some low-level copy edits for spelling and punctuation
• Renamed some screenshots to provide more meaningful names

Please let me know if you have any questions.

• [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

[Dan-Heath]

Hello @jeffpearce , I created this PR as part of the Hacktoberfest docs-to-code project. I think it is ready for review. Please take a look and let me know if you have any questions or if there are any changes you'd like me to make. Thank you!

[jeffpearce]

Well, the build failed, but I can't see how this PR caused it. I'll go ahead and merge this and look int it later

[Dan-Heath]

Well, the build failed, but I can't see how this PR caused it. I'll go ahead and merge this and look int it later

Hmm... thanks. If it did have anything to do with this PR and I can help fix it, please let me know.