Add support for boot script

[praste]

I created a init.d folder under deb folder. I then added mapper to move file in init.d folder to /etc/init.d. However variable substitution for placeholder [[name]], [[version]] etc, did not work

Can we make using init.d as a standard folder (just like we use control folder to store all control files) to store boot script and support variable substitution as well.

[muuki88]

I recommend against standard folders for system loaders. Currently there are three systems in use

• SystemV (init.d)
• Upstart (init)
• SystemD (somewhere else)

But enable variable substitution for specific files would definitely be nice.

[tcurdt]

Flexible variable substitution is on the roadmap. (see #195 )