Only syntax errors

Implements dyncode update for handled sites in lodelsites. solves #260

Now we are able to control EditorialModel load process at runtime
for lodelsites handled sites dyncode generation

Introduce a new dependencie between lodelContext & multisite plugin

Now the context manager handles lodelsites paths

Thoses modification has two goals :
- make lodelcontext fit with the new FS organisation implemented by the
lodelsites datasource
- make the dyncode exposure more "flexible"

Note : no solution implemented for MONOSITE

At this point the loader in lodel/plugins/multisite/run.py is theorically
complete & correct. But some features are missing in order to be able
to test & debug it ( refs #275 ).

Now we are able to insert a lodelsite

no debug has been made on those piece of code

As a primary_key field has to be unique, added a check at DataHandler
instanciation to make sure a field set as a pk is not set as non-unique

Warning, may contains some bugs !!!

For the moment there is only uninstalling by name that works because #207

Clean take care of deleting plugins with same name and different versions
(the lower versions will be deleted)

Now in verbose mode we are printing all plugins, even those with duplicated
names and different versions

the action is named plugins

For the moment a new action for lodel_admin has been added : list-plugins
With two options : verbosity and output formatted in CSV

fixes #205

Now discover is run when we want to know the list of installed plugins.
+ bugfix in module name generation (only in the constructor) to take care
of possible subdirs

Removed the "from .datasource_plugin import DatasourcePlugin" in
Plugin.register