remove a portion of sample data in default image

[Bill Filler]

With our dogfooding release at end of May, we should not include some of the sample data we currently include as it's not useful to the user.

Specifically:
1) Sample data in messaging menu
Remove chewie_messaging_populate_menu from /etc/phone|tablet-services in ubuntu-session package

2) Contacts
- Remove manage-address-books.py create from /etc/phone|tablet-services in ubuntu-session package
- Currently contacts information demo-assets package. Split into multiple binary packages and move sample contact related stuff into demo-assets-contacts. Do not include this by default.

3) Sample conversations in telephony-app
Currently defined in demo-assets package. Split into multiple binary packages and move sample conversation related stuff into demo-assets-telephony. Do not include this by default.

4) Sample photos
Currently in demo-assets package. Split into multiple binary packages and move sample photos into demo-assets-photos. Do not include this by default.

5) Sample videos
Currently in demo-assets package. Split into multiple binary packages and move sample videos and lens related files into demo-assets-videos. Include this by default.

6) Sample Music
Currently in demo-assets package. Split into multiple binary packages and move sample music and lens related files into demo-assets-music. Include this by default? Not sure.