Refactored space removal in configuration file. Now each block has:
* starts with an empty line **IF** it has anything to state
* no empty line within a block (of servers, pools, otherparams)

Pool and server configuration may have different options but it's not
currently possible.
In order to solve that, the template is changed to accept pool
or server specification as a dictionnary, specifying at least the
pool/server name and if wanted the pool/server options. If no options
are specified, it'll use chrony.options.
In order to not break anything the template is checking if the server/pool
specification is a dictionnary or not, and acts accordingly.

Fixes: #27
Signed-off-by: Arnaud Patard <apatard@hupstream.com>

BREAKING CHANGE: `chrony.removed` replaced by `.clean` states.