LXD-based development environment

[nooreldeenmansour]

This is a development environment based on LXD VMs. Current limitation is the lack of GDM compatibility out-of-the-box

[3v1n0]

As mentioned elsewhere, I think we should avoid having too much scripting (we've even too much) to maintain, but rather use a proper build system using meson that would allow to build and generate and install things easily, and that can be used both for development purposes and for generating the debian package.

So that a meson install will just do all for everybody, whether is a local install, lxd, debian package or anything else.