feat: add datanode prefix to datanode's data home

[waynexia]

This patch add prefix (datanode.x) to the data home path

prev:

DEBUG: component/cluster.go:90] run binary 'greptime' with args: '[--log-level=info datanode start --node-id=1 --metasrv-addr=0.0.0.0:3002 --rpc-addr=0.0.0.0:14101 --http-addr=0.0.0.0:14301 --data-home=.gtctl/mycluster/data/home --wal-dir=.gtctl/mycluster/data/datanode.1/wal]', log: '.gtctl/mycluster/logs/datanode.1', pid: '469492'
DEBUG: component/cluster.go:90] run binary 'greptime' with args: '[--log-level=info datanode start --node-id=2 --metasrv-addr=0.0.0.0:3002 --rpc-addr=0.0.0.0:14102 --http-addr=0.0.0.0:14302 --data-home=.gtctl/mycluster/data/home --wal-dir=.gtctl/mycluster/data/datanode.2/wal]', log: '.gtctl/mycluster/logs/datanode.2', pid: '469493'

after:

DEBUG: component/cluster.go:90] run binary 'greptime' with args: '[--log-level=info datanode start --node-id=1 --metasrv-addr=0.0.0.0:3002 --rpc-addr=0.0.0.0:14101 --http-addr=0.0.0.0:14301 --data-home=.gtctl/mycluster/data/datanode.1/home --wal-dir=.gtctl/mycluster/data/datanode.1/wal]', log: '/.gtctl/mycluster/logs/datanode.1', pid: '484027'
DEBUG: component/cluster.go:90] run binary 'greptime' with args: '[--log-level=info datanode start --node-id=2 --metasrv-addr=0.0.0.0:3002 --rpc-addr=0.0.0.0:14102 --http-addr=0.0.0.0:14302 --data-home=.gtctl/mycluster/data/datanode.2/home --wal-dir=.gtctl/mycluster/data/datanode.2/wal]', log: '.gtctl/mycluster/logs/datanode.2', pid: '484028'

[shawnh2]

if this is the case, the d.dataHome should be type []string

and also in d.Delete method, use for...range to delete each file in d.dataHome