[yb-ctl] make remove_node destroy node data

[jaki]

Jira Link: DB-10819
Currently, remove_node and stop_node commands do the same thing: stop the node. There is no way to kill a node. Add that ability, preferably by changing the behavior of the redundant remove_node command.

[jaki]

Actually, it seems remove_node does kill the process (along with --master flag), but status shows it still.

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| Node 2: yb-tserver (Stopped), yb-master (Stopped)                                                |
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[jaki]

Actually, I think that this is somewhat a somewhat reasonable issue:

• yb-ctl stop stops all nodes without removing data
• yb-ctl destroy stops all nodes and removes data

Similarly, we should have

• yb-ctl stop_node stop the node without removing data
• yb-ctl remove_node (or destroy_node) stop the node (both master and tserver) and remove the data

status should not show destroyed nodes (skip over them). UI pages should also not show these nodes as DEAD because they are gone for good, irrelevant. add_node should keep counting upwards, never going back to destroyed node numbers.