Make the host-id file configurable

[hulto]

Is your feature request related to a problem? Please describe.

• Rn if you run imix as a low priv user on linux it will get a new host-id every time.
• This was also an issue with Windows.

Describe the solution you'd like
May be worth just making this configurable in the agent.
Adding a field to the JSON for host-id file path

Describe alternatives you've considered
Na

Additional context
Na

[jabbate19]

When you say the JSON, which JSON are you referencing? I'm guessing this was before we moved from imix config JSON to env vars, so how would you advise doing this in the new practice?

[hulto]

Yeah this was pre migration.
Let's make it a compile time ENV var with sensible defaults of world writable locations for Linux and Windows.

[hulto]

Resolved in #785