backups: Add support for creating fully uncompressed backups (#3378)

Hassio supervisor saves backups in tar files that contains compressed
tar archives, this is convenient when such backups are kept in the same
environment or need to be transferred remotely, but it's not convenient
when they will be processed using other backup tools such as borg or
restic that can handle compression, encryption and data deduplication
themselves.

In fact deduplication won't actually work at all with hassio compressed
backups as there's no way to find common streams for such tools (unless
we make them to export the archives during importing as borg's
import-tar can do), but this would lead to archives that are not easily
recoverable by the supervisor.

So, make possible to pass a "compressed" boolean parameter when creating
backups that will just archive all the data uncompressed.

It will be then up to other tools to manage the archives compression.

supervisor/backups/validate.py

@@ -7,6 +7,7 @@ from ..const import (
     ATTR_AUDIO_INPUT,
     ATTR_AUDIO_OUTPUT,
     ATTR_BOOT,
+    ATTR_COMPRESSED,
     ATTR_CRYPTO,
     ATTR_DATE,
     ATTR_DOCKER,
@@ -65,6 +66,7 @@ SCHEMA_BACKUP = vol.Schema(
         vol.Required(ATTR_TYPE): vol.Coerce(BackupType),
         vol.Required(ATTR_NAME): str,
         vol.Required(ATTR_DATE): str,
+        vol.Optional(ATTR_COMPRESSED, default=True): vol.Boolean(),
         vol.Inclusive(ATTR_PROTECTED, "encrypted"): vol.All(
             str, vol.Length(min=1, max=1)
         ),