Simplify roles a bit

We now have an attribute that helps us know when a node is a founder or
not. The end goal will be to get rid of the founder role and have the
wrapper (for instance, crowbar) set this attribute on one node.
Install pacemaker packages before corosync

That way, pacemaker is already there when we start corosync, which is
something that we need.
Move RHEL-specific bit out of founder-exclusive code path
Add attributes to choose whether to install graphical UI or not

It might not make sense to install that for everyone, so make this an
option disabled by default.
Remove demo attribute
Allow setting up password for hacluster user
Revert "pacemaker rpm is required before openais service starts"

This is not needed anymore, as we reworked the interaction between
pacemaker and corosync cookbooks.

This reverts commit 4428fc57678a32acf7106f2d81aafc83cec0fd88.
Install openstack-resource-agents from here

It's not extremely clean to do openstack bits here, but it simplifies
many things. If this barclamp will be used for non-openstack setups too,
then we can actually have Crowbar orchestrate things to tell the
cookbook about which resource agents to install.
Better label for Hawk link
Load node only when required during validation
Make barclamp appear in list of OpenStack barclamps for now

This is probably not the best thing right now, but we have no HA
category so far... At least, with this, we get some visibility.
Add pacemaker_vip_primitive definition helper for cookbooks
Do not include corosync recipe from pacemaker when under chef-solo

This breaks the CI.