Fix config set compression type didn't take effect

[xiaobiaozhao]

In this PR, we also refactor the c-style ConfigEnum array into the std::vector, the main reason is to make it easier to adopt dynamic config enums like the compression types. And for the test case, it's a bit hard to test if the compression type takes effect in underlying storage because we only enabled it when the levels >= 2. But will check it manually to make sure if works.

This closes #1560

[PragmaTwice]

the code does not look well to me, some fixes need to be pushed

[caipengbo]

I think the SetCompressionOption parameter value is the name of the compression algorithm. We get rocksdb::CompressionType by map[name](name->CompressionType), and then pass it to SetOptions, in SetOptions static_cast it to rocksdb::CompressionType.

[git-hulk]

@PragmaTwice @xiaobiaozhao @caipengbo I minor refactor the PR, PTAL again.

[git-hulk]

I have tested if the config set command works on my side:

Set the compression to LZ4:

2023/07/14-20:45:08.518174 6158610432 [db/db_impl/db_impl.cc:1195] SetOptions() on column family [default], inputs:
2023/07/14-20:45:08.518210 6158610432 [db/db_impl/db_impl.cc:1198] compression_per_level: kNoCompression:kNoCompression:kLZ4Compression:kLZ4Compression:kLZ4Compression:kLZ4Compression:kLZ4Compression

then use redis-benchmark -p 6666 -n 1000000 -r 5000000 -t set -d 1024 to write the data, and check the db LOG to see if the compression was used:

2023/07/14-20:50:15.181736 6156890112 (Original Log Time 2023/07/14-20:50:15.181594) [db/compaction/compaction_job.cc:888] [metadata] compacted to: files[0 1 13 0 0 0 0] 
max score 0.93, MB/sec: 39.1 rd, 4.5 wr, level 2, files in(1, 1) out(1 +0 blob) MB 
in(58.0, 2.6 +0.0 blob) out(7.1 +0.0 blob), read-write-amplify(1.2) write-amplify(0.1) OK, 
records in: 89927, records dropped: 3779 output_compression: LZ4

[caipengbo]

LGTM