[Feature] Allow read-only config file

[DrakeTDL]

Is your feature request related to a problem? Please describe. My use-case for this is, I am attempting to make a module NixOS/nixpkgs. A road-block I am experiencing is that when Stash attempts to read the config file, it errors because it's in a read-only filesystem.

Describe the solution you'd like

1. Allow Stash to read the config regardless of its ability to writable and print a warning message to stdout/stderr
2. Have an env/flag to bypass the startup write check.

Describe alternatives you've considered

1. Copy the file to a read-write filesystem.
2. Do nothing and let the user manage the config imperatively.

Additional context If implemented, a user tries to edit a setting from the UI; I'd imagine a toast (or some sort of popup) message and/or a stdout/stderr log detailing which setting a user tried to edit.