[CELEBORN-1640] NettyMemoryMetrics supports numHeapArenas, numDirectArenas, tinyCacheSize, smallCacheSize, normalCacheSize, numThreadLocalCaches and chunkSize

[SteNicholas]

What changes were proposed in this pull request?

NettyMemoryMetrics supports numHeapArenas, numDirectArenas, tinyCacheSize, smallCacheSize, normalCacheSize, numThreadLocalCaches and chunkSize from PooledByteBufAllocatorMetric. Meanwhile, remove server_ prefix from metric name of netty memory metric in monitoring.md.

Why are the changes needed?

PooledByteBufAllocatorMetric provides the following API to support netty memory metrics:

public int numHeapArenas() {
  return this.allocator.numHeapArenas();
}

public int numDirectArenas() {
  return this.allocator.numDirectArenas();
}

public List<PoolArenaMetric> heapArenas() {
  return this.allocator.heapArenas();
}

public List<PoolArenaMetric> directArenas() {
  return this.allocator.directArenas();
}

public int numThreadLocalCaches() {
  return this.allocator.numThreadLocalCaches();
}

public int tinyCacheSize() {
  return this.allocator.tinyCacheSize();
}

public int smallCacheSize() {
  return this.allocator.smallCacheSize();
}

public int normalCacheSize() {
  return this.allocator.normalCacheSize();
}

public int chunkSize() {
  return this.allocator.chunkSize();
}

public long usedHeapMemory() {
  return this.allocator.usedHeapMemory();
}

public long usedDirectMemory() {
  return this.allocator.usedDirectMemory();
}

NettyMemoryMetrics only supports usedHeapMemory and usedDirectMemory, which could support numHeapArenas, numDirectArenas, tinyCacheSize, smallCacheSize, normalCacheSize, numThreadLocalCaches and chunkSize from PooledByteBufAllocatorMetric.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Celeborn Grafana Dashboard

[SteNicholas]

Ping @FMX, @RexXiong.