Doc has store "false" not store "true"

Came from 3465e69e83a4f9f375fb9486741db51efb800837 due to changing "yes" to "false".

Closes #9075
Add index.data_path setting

This allows specifying the path an index will be at.

`index.data_path` is specified in the settings when creating an index,
and can not be dynamically changed.

An example request would look like:

POST /myindex
{
  "settings": {
    "number_of_shards": 2,
    "data_path": "/tmp/myindex"
  }
}

And would put data in /tmp/myindex/0/index/0 and /tmp/myindex/0/index/1

Since this can be used to write data to arbitrary locations on disk, it
requires enabling the `node.enable_custom_paths` setting in
elasticsearch.yml on all nodes.

Relates to #8976
[CORE] Delete shard content under lock

Once we delete the the index on a node we are closing all resources
and subsequently need to delete all shards contents from disk. Yet
this happens today under a lock (the shard lock) that needs to be
acquried in order to execute any operation on the shards data
path. We try to delete all the index meta-data once we acquired
all the shard lock but this operation can run into a timeout which causes
the index to remain on disk. Further, all shard data will be left on
disk if the timeout is reached.

This commit removes all the shards data just before the shard lock
is release as the last operation on a shard that belongs to a deleted
index.