##### SUMMARY
Since `add_host` and `group_by` actions only modify the runtime inventory, hosts/groups/vars added by them don't survive a `meta: refresh_inventory` call (since that call completely clears the runtime inventory). 

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
InventoryManager

##### ADDITIONAL INFORMATION
After some internal discussion, the general consensus seemed to be that this behavior is an undesirable default. The `add_host` and `group_by` actions should manage a more persistent state independent of the runtime inventory, then apply their changes to the running inventory. When a `meta: refresh_inventory` occurs, the normal dynamic inventory clear/refresh should happen, then reapply the add_host/group_by state. This should probably be the default behavior, but a config switch or a different `meta` action (or an arg to it) to emulate the current behavior could also be created if necessary.

"""
        Takes a single pattern and returns a list of matching host names.
        Ignores intersection (&) and exclusion (!) specifiers.
        The pattern may be:
            1. A regex starting with ~, e.g. '~[abc]*'
            2. A shell glob pattern with ?/*/[chars]/[!chars], e.g. 'foo*'
            3. An ordinary word that matches itself only, e.g. 'foo'
        The pattern is matched using the following rules:
            1. If it's 'all', it matches all hosts in all groups.
            2. Otherwise, for each known group name: