refactor: move write_batch_delete into rocksdb_wrapper

[levy5307]

What problem does this PR solve?

move write_batch_delete into rocksdb_wrapper, and use it to reimplement multi_remove

• Manual test (add detailed scripts or steps below)

>>> use temp
OK
>>> multi_set hash sort1 value1 sort2 value2 sort3 value3 sort4 value4
OK

app_id          : 2
partition_index : 4
decree          : 9
server          : 10.232.55.210:34802
>>> multi_get hash
"hash" : "sort1" => "value1"
"hash" : "sort2" => "value2"
"hash" : "sort3" => "value3"
"hash" : "sort4" => "value4"

4 key-value pairs got, fetch completed.

app_id          : 2
partition_index : 4
server          : 10.232.55.210:34802
>>> multi_del hash sort1
1 key-value pairs deleted.

app_id          : 2
partition_index : 4
decree          : 10
server          : 10.232.55.210:34802
>>> multi_get hash
"hash" : "sort2" => "value2"
"hash" : "sort3" => "value3"
"hash" : "sort4" => "value4"

3 key-value pairs got, fetch completed.

app_id          : 2
partition_index : 4
server          : 10.232.55.210:34802
>>> multi_del hash sort2 sort3
2 key-value pairs deleted.

app_id          : 2
partition_index : 4
decree          : 11
server          : 10.232.55.210:34802
>>> multi_get hash
"hash" : "sort4" => "value4"

1 key-value pairs got, fetch completed.

app_id          : 2
partition_index : 4
server          : 10.232.55.210:34802
>>> multi_del hash sort4
1 key-value pairs deleted.

app_id          : 2
partition_index : 4
decree          : 13
server          : 10.232.55.210:34802
>>> multi_get hash

0 key-value pairs got, fetch completed.

app_id          : 2
partition_index : 4
server          : 10.232.55.210:34802