[sdk-manage] add options to support usage in chroot

Now supports target creation and removal

Signed-off-by: Juha Kallioinen <juha.kallioinen@jolla.com>
[sdk-assistant] initial commit

Signed-off-by: Juha Kallioinen <juha.kallioinen@jolla.com>
[sdk-assistant] added bash completion

Signed-off-by: Juha Kallioinen <juha.kallioinen@jolla.com>
Merge pull request #12 from sailfish-sdk/sdk-manager-for-chroot

Add sdk-assistant for chroot ops