[MONIT-4003] Add default node selector for all components

Until now all the components that were not a daemonset and needed to be deployed on a node contained a config option to indicate a node selector for the allocation. This commits adds a new global option that allows to set a node selector that will be applied to all the components that do not declare one. If any component declares a node selector this last one will have always more priority.

This has been tested locally rendering the template setting and unsetting the global node selector and the individual ones for each affected component.

JIRA Refs:

• MONIT-4003