Include PSGI app to expose cluster to other servers

Using a custom router as web framework here is not yet possible.
Include PSGI app to expose cluster to other servers

Using a custom router as web framework here is not yet possible.
added upstart script for the PSGI

(this is temporary if properly integrated with nginx or whatever)
RESTClient is now part of core

* As it is used by ha and remoteservices module.
* run-pending-ops has been moved to core as well
* RESTClient has been unit tested a little
Merge branch 'ejhernandez/ha-base-multi-node' of github.com:Zentyal/zentyal into ejhernandez/ha-base-multi-node
Added empty to NodeList
Document hostName and fqdn for developers
Added icon for new zentyal-ha module
Added localNode attribute to nodelist elements
Added several capabilities to ha.psgi daemon

* Decode JSON from body
* Added return simple scalar
manage ha-psgi with upstart
Merge branch 'ejhernandez/ha-base-multi-node' into jacalvo/ha-confrepl

Conflicts:
	main/core/ChangeLog
Adding support to named parameters in Router

We are now copying without blush to Django URL dispatcher
added route and basic handlers for conf replication (WIP)
replicate conf of some gateway/utm modules
added openvpn to list of modules to replicate
Adapted to new cluster configuration interface
replicate to all nodes
Bootstraping cluster is now even more nice

* Stored cluster conf in Redis
* Unit test cluster configuration method
Fix unit test name