Summary:
This diff adds multiple pre-packaged linux headers into the PEM/stirling base image.

Stirling then chooses the closest Linux kernel match in case it can't find the host headers.

Test Plan: Some tests added, and tested manually too.

Reviewers: yzhao, zasgar, #engineering

Reviewed By: zasgar, #engineering

JIRA Issues: PP-1863

Differential Revision: https://phab.corp.pixielabs.ai/D4605

GitOrigin-RevId: 02fdf0332ce283ac8d31cff06d5645cb48ec98f2