jenkins: add page

[sri-sethu]

If you are a new contributor to the project, do not use AI to generate pages. We will close any PR with a suspicion of AI usage.

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR contains at most 5 new pages.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):

[tldr-bot]

The build for this PR failed with the following error(s) at commit
5f1231ec5732f66fbf184eb99bb6170714e8ade9:

pages/common/jenkins.md:1: TLDR014 Page should contain no trailing whitespace
pages/common/jenkins.md:3: TLDR003 Descriptions should start with a capital letter

Please fix the error(s) and push again.

[TheRootDaemon]

I think you have checked out from rni instead of main.

It won't be a problem though since we squash and merge the PRs. But it is important to know your mistakes.

[TheRootDaemon]

Update this placeholder across the page, it make more sense to have {{jenkins_server_url}} as the placeholder rather than what was there already.

[Managor]

I've been procrastinating with reviewing this because the command is not a direct CLI word, but uses java instead. But I guess it's alright. The purpose here is to be a quickstart guide for anyone who wants to use the tool.

[Managor]

@sri-sethu