First implementation of TOFS for:
nginx_config, passenger_config, servers_config and snippets
Introduced tplroot on modified files as well
Fixed GH link of nginx.conf file in docs/TOFS_pattern.rst
Fixed test for snippets name pillar

BREAKING CHANGE: all previous `nginx` based configurations must be reviewed;
`nginx.ng` usage must be promoted to `nginx` and any uses of the original
`nginx` will have to be converted.

With this one can now also write

 - include:
   - file1
   - file2

Rather than only

 - include: file1
 - include: file2