Froyo owned changes in terminology

This is a ticket to change references from the roles "master" to "server", "compile masters" to "compilers" (largely done previously), and "master of masters" to "primary" or "main".

Concepts previously termed "whitelists" and "blacklists" should now be termed "allowlists" and "denylists" respectively.

Namespaces, classes, parameters, and settings that require changing should be changed, but the previous terms should be aliased to the new so that new versions may be used in a backwards compatible way for the foreseeable future.

The git "head" branch for development should be changed from "master". New "head" branches should be termed "main".

This is to happen in all Froyo owned projects (public and private) and their respective docs, including puppetserver, puppetserver-ca-cli, r10k, file-sync, code-manager, and the wider trapperkeeper ecosystem.