add rle v2 encoding for segment v2

[kangpinghuang]

Now the default encoding for integer type of segment v2 is bitshuffle, performance test shows that it has some drawbacks, like every time decode the page, we should decompressed by using lz4, and the encoding efficiency is not high, cost more 40% space than relv2.
for performance, I decide to add rlev2 encoding for segment v2.