Prepare for offline removal and addon additions. (#18)
Prepare for offline removal and addon additions. (#18)

- Removes online and offline snapshot packages.
- Adds openhab2, openhab2-addons and openhab2-addons-legacy packages.
- Separated out with different configs using an "if contains" statement, so that they may share exact version numbers and be triggered using buildSnapshot.

For users:
- `apt-get install openhab2` will automatically remove openhab2-online or openhab2-offline in the process.
- `apt-get install openhab2-addons openhab2-addons-legacy` will also ask to install openhab2 if not already on.
- `apt-get install openhab2 openhab2-addons` gives same functionality as the old `apt-get install openhab2-offline`.

Signed-off-by: Ben Clark <73675debcd8a436be48ec22211dcf44fe0df0a64@benjyc.uk>
theoweiss/openhab-linuxpkg,abedwardsw/openhab-linuxpkg