The inclusion of subprojects is mostly to get easy access to the library
without having to install it. It makes in most cases no sense to run
tests of subproject when we are not developing it.

In general I am sure that including tests from subproject makes a lot of
sense, for example when we split tests and application to the separate
repositories. At the same time we are really not doing that here.

Meson provides easy subproject inclusion trough implicit dependency.
We use project name here to be systematic and provide linking with
libfoo. The library does not have to be installed when this project is
included as subproject using wrap file 'subprojects/c-template.wrap'
with content:

  [wrap-git]
  url = https://gitlab.nic.cz/turris/c-template.git
  revision = master

This moves release.sh script to the shared script. The only difference
between projects is the name of the project. We can provided that as
argument from the CI and thus we can have it only in one location.

The library has to specify which headers to install explicitly.

The meson build has to be build in subdirectory that adds automatically
its own .gitignore file to not interfere with git repository. The result
is that we actually do not need any our own gitignore. We should now
include all files in the git repository.

This project of course does not contain autotools now.

This is heavily improved common code that we use in multiple projects.
To have minimal project prepared for fork should give us way faster C
projects creation. Another advantage is that we can merge new changes to
existing projects and that way ensure that fixes to common template are
reliably propagated.

This contains only bare-bone readme.