Today the `elasticsearch-shard remove-corrupted-data` tool will only truncate a
translog it determines to be corrupt. However there may be other cases in which
it is desirable to truncate the translog, for instance if an operation in the
translog cannot be replayed for some reason other than corruption. This commit
adds a `--truncate-clean-translog` option to skip the corruption check on the
translog and blindly truncate it.
With the removal of node.max_local_storage_nodes, there is no need anymore to keep the data in
subfolders indexed by a node ordinal. This commit makes it so that ES 8.0 will store data directly in
$DATA_DIR instead of $DATA_DIR/nodes/$nodeOrdinal.
Upon startup, Elasticsearch will check to see if there is data in the old location, and automatically
move it to the new location. This automatic migration only works if $nodeOrdinal is 0, i.e., multiple
node instances have not previously run on the same data path, which required for
node.max_local_storage_nodes to explicitly be configured.