Summary: Updates the doc strings in the makefile and cleans up unused code.

Test Plan: `make help`

Reviewers: michelle, oazizi, nserrino, #engineering

Reviewed By: oazizi, #engineering

Differential Revision: https://phab.corp.pixielabs.ai/D2447

GitOrigin-RevId: 5e7e8a3a42705623f473beb0bd27087e211316a4