lxc-debian: fix formatting

added space ">/" -> ">  /"

Signed-off-by: Alexander Dreweke <alexander@dreweke.net>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
lxc-debian: standardize formatting

Signed-off-by: Alexander Dreweke <alexander@dreweke.net>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
lxc-debian: added support for package installation

- added --mirror, --security-mirror and --package parameters
- generate source.list
- install packages into final lxc instance

Signed-off-by: Alexander Dreweke <alexander@dreweke.net>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>