Add download instruction to other dists on base deb.

[alexeysvrv]

Hi. Please, add download instruction to other dists on base deb. on download page. I mean to add the line echo "deb https://pkg.tox.chat/debian stable release" | sudo tee /etc/apt/sources.list.d/tox.list to instruction. Since it is not documented and this new users will not know. Personally, I use this repository as Trusty is not officially supported, although it is officially an LTS release and it should be supported until 2019

[nurupo]

Over a year ago we were packaging statically linked binaries of Tox clients bundled in a .deb. We thought that we could make just a single deb package that would work on all Debian-based systems. That's what the release repository is. There were many issues with it, but the main issue was that it required the user to have the compatible versions of glibc, and other libraries, as apparently not everything can be statically linked into the binary, so it didn't work for many of the distributions and there were many complains.

A year ago we decided to make proper shared packages that would have dependencies on other packages available in the distribution's repository, instead of statically linking everything into the binary. The binaries that are packaged are built in chroots of the distribution versions that the packages target, e.g. a package for Ubuntu Xenial is built in Ubuntu Xenial chroot, using Ubuntu Xenial's glibc and so on, so that there would be no issue with library ABI incompatibility.

We don't want to advertise the release repository on our website because of the issues statically linked binaries have and because those static packages and not really maintained by anyone anymore, no new packages would be added in release repository and if some package breaks, no one would fix it. The shared packages have a lot less issues and are maintained by @Encrypt. We advise users not to use the release repository if they can use one of the repositories providing debs with dynamically linked binaries.

So yeah, release package repository is pretty much deprecated and we'd like to remove it from the package server altogether, but we don't do that just yet because it seems to be still used and packages it provides seem to still be functional on some systems.

There are no shared packages of toxcore and clients for Ubuntu Trusty because it lacks dependencies required to build toxcore and/or clients.