Allow to set a passphrase file location per stash

[nir0s]

When a stash is initialized, a passphrase.ghost file is generated for it. A user can explicitly pass a passphrase in the API and the CLI or set an environment variable else the file is searched for in different locations.

If a user works with multiple stashes, they have to explicitly pass the passphrase as only the passphrase.ghost file is looked up.

Providing an API for setting a location in the storage for where to find the passphrase file would allow users to use multiple passphrase files easily.

The API could be implemented somewhat like so:

stash.init()

stash.set_passphrase('/etc/ghost/my-stash.passphrase.ghost')

Every time a user uses a specific stash, the passphrase file will be looked up in the set position.

[nir0s]

This might create too much ambiguity with regard to where the passphrase is taken. Currently, it can be passed using an env var, a cli flag, three file system locations and the API. Adding this might confuse the user as it provides a second explicit method.

Let's think about it again.

[nir0s]

Seems like this would introduce too much complexity. Closing for now.