Add LZ4 compressor

- provides significant performance improvement for saving (37% in testing)
- at the cost of double the storage size (in testing)

build.gradle

@@ -199,6 +199,8 @@ dependencies {
     include(implementation 'redis.clients:jedis:5.1.0')
     include(implementation('org.rocksdb:rocksdbjni:8.10.0'))
     include(implementation 'org.apache.commons:commons-pool2:2.12.0')
+    //include(implementation 'org.tukaani:xz:1.10')
+    include(implementation 'org.lz4:lz4-java:1.8.0')
     //implementation 'org.rocksdb:rocksdbjni:8.10.0'
     //implementation 'redis.clients:jedis:5.1.0'
 }