feat(syncthing): impl encryptionPasswordFile

[plustik]

Description

Syncthing allows setting a password for specific devices a specific folder is shared with. Files are encrypted before being send to this device. The password can be set using the API by setting the encryptionPassword property of the given device in a folder config.

Previously it was not possible to use this functionality of Syncthing with this Home Manager module, because the the devices attribute of a configured folder only accepted strings. The module than created a device item as expected by the Syncthing API, but only set the deviceID attribute of this item, but neglected the optional encryptionPassword attribute.

The changes of this PR enable the usage of encrypted folder sharing, by adjusting the handling of configured folders. The items of the devices list of a folder config may now be attribute sets instead of strings. While strings are handled in the same way as previously, the attribute sets must contain the deviceID attribute may additionally contain an encryptionPasswordFile attribute, whose value must be a path to a file, whose content will be used as the value for the encryptionPassword attribute send to Syncthing.

Checklist

• Change is backwards compatible.

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Maintainer CC

@rycee