Automate more things

In order to handle a higher rate of CVEs efficiently, we need to automate more of that work.

Start with some cleanup:

• scripts/kernel_sec: Use pathlib for filename manipulation

Add more functionality to the kernel_sec module:

• scripts/kernel_sec: Add save method to issue class
• scripts/kernel_sec: Allow creating new issue files
• scripts/kernel_sec: Add types to support comparison of kernel versions
• scripts/kernel_sec: Add Status class and parse_status_full() function
• scripts/kernel_sec: Add variable for repository base directory
• scripts/kernel_sec: Add functions to maintain Debian version state

Add some new scripts:

• Add set-version script to maintain Debian version information
• Add import-korg-vulns script to import issue data from vulns.git

And update data with those scripts:

• Add initial Debian versions file
• Import issue data from vulns.git