Be aware of already existing Ngrok config file

[AndyTitu]

Based on @arunsathiya 's additions this PR looks deeper into handling an already existing config file.

Thought process

check if --config flag is specified with a path to the already existing config file. If yes, read that file, inject it with sensitive information from 1Password and provision it via in-memory file provisioning. If not, use the default locations for the config file. In this way, configs are also present alongside credentials for each run.

[AndyTitu]

@arunsathiya @russorat it would be awesome if you could test these changes against your local ngrok setup as well. You might have some configuration that I missed (i.e. is it okay to use time.Duration for connect_timeout in config, or should I just stick to int?).

[arunsathiya]

This looks like a great next step, @AndyTitu, thank you. 🙌🏽

I haven't taken a proper look at the changes so far, but some quick tests seem to run well for me.

I ran into an error but I am unable to reproduce it at the moment, nor do I remember the exact error message. I'll keep testing for another day or two and followup with my findings.

A minor note in the meantime though: I see several "AuthToken" in the struct definition. Should we update that to "Authtoken", in alignment with the field name?

[AndyTitu]

Linter fails unexpectedly: #195. Solving this in #196