Improve a plugin tutorial and blog post

[MarkEWaite]

Improve a plugin tutorial and blog post

Describe some of the common, small, useful steps that a new contributor can offer to improve a plugin. Uses the notes from the DevOps World 2021 "Contributing to Open Source" workshop with further refinements from Darin Pope, Dheeraj Singh Jodha, Meg McRoberts, and Jean-Marc Meessen.

This is a draft that will need significant improvements before it is ready to be published.

• Adopt a plugin blog post draft
• Checking if I can push code
• reverting the changes to README.md
• Add entry point for adopt a plugin tutorial
• Make ci.jenkins.io a hyperlink
• Include the Add a Jenkinsfile page
• Fix blog data
• Added a sub-heading
• Adopt a plugin tutorial and blog post
• Goal: publish by 23 Nov 2021
• Extract common git operations to reusable files
• Add content to update parent pom
• Add content to update base Jenkins version
• Add section to update scm URL
• Fix white space
• Add videos
• Add video for spotbugs checks
• Remove unneeded backslash from https protocol
• Chapter 3: Review build status
• Chapter 7: Automate dependency update checks
• Chapter 8: Enable incrementals
• Chapter 9: Convert API to plugin dependencies
• Chapter 10: Replace JSR-305 annotations
• Chapter 11: Replace deprecated JUnit method
• Chapter 12: Replace joda-time with Java 8 time
• Minor grammatical improvement
• Chapter 13: Use plugin bill of materials
• Chapter 14: Add a contributing guide
• Chapter 15: Migrate doc to GitHub
• Chapter 16: Add a link to Report an Issue
• Chapter 17: Improve pipeline documentation
• Chapter 18: Improve Javadoc
• Chapter 19: Add a CasC automated test
• Chapter 20: Add a round trip test for config
• Move tutorial images to matching directory
• Create a branch instead of checkout a branch
• Modernize rather than adopt
• Begin renaming from adopt to modernize
• Compile code before submitting pull request
• Add spotbugs verify and suppression guidance
• Improve a plugin rather than modernize it
• Reorder improve a plugin sectiosn
• Rephrase blog post
• Retain more readers with embedded video
• Reorder chapter contents
• Reduce risk of adding untracked files
• Link to parent pom additional changes
• More description of use the plugin bom
• Include link to official documentation page
• Add dependency check automation video