Omnia 4849 - require-root for install

I'm very excited about the work in #4849

An initial observation that I've been pondering. Omnia during install requires write access to `/etc/omnia` (and another location in `etc`). `etc` is typically writable only by root. Today to install Omnia you need root access.

I'm opening this issue to discuss if this is a sensible design constraint.

I feel like require-root for install may be desirable:
- Omnia is a provisioning tool that may have a large scope of influence. It does root like things to the system.
- We want to use standard OS features for audit, logging, etc. Having a 'root-required' step makes this easy to setup during install.

Also, I feel like require-root may not be desirable:
+ writing to `/etc` is an artificial requirement - we could change `/etc/omnia` to a user configurable location.

On balance, I think my instinct is that we should require-root (the current behavior) for install. Anyone have alternative thoughts?

Read the installation work in #4849 and inspect how the current install writes to /etc/omnia and the other etc location. No file or test is named here; done requires a decided policy on root-required installation versus a user-configurable location, with that decision reflected in the install behavior or project documentation.

Written by the indexing model from the issue text.