Tool for clearing ticket parser cache

[s-sabitova]

Currently node's ticket parser cache may be erased only by restarting the node.

However, there are situations when clearing the cache should be triggered manually - e.g. when an error ticket is "stuck" in the cache and needs to be refreshed. So admin should have a way of doing it without restarting the nodes.

Up for discussion:

• maybe this action should trigger clearing ticket parser cache across the entire cluster, not just one selected node
• add an option to erase only error tickets