Logql benchmark and performance improvement.

[cyriltovena]

Hello !

This PR adds a benchmark for the LogQL engine and also improve allocations and therefore cpu usage when doing metrics queries. Improvement is around 40% in term of CPU and 80% for allocation/memory usage.

I can see there is still ways to improve metrics queries, but I didn't wanted to change the implementation too much, since we might add more to the language in the future.

Here is the result:

❯ benchcmp old.txt new.txt
benchmark                         old ns/op      new ns/op      delta
BenchmarkRangeQuery100000-16      3969200        1980841        -50.09%
BenchmarkRangeQuery200000-16      25067162       5204838        -79.24%
BenchmarkRangeQuery500000-16      2036930499     1394141266     -31.56%
BenchmarkRangeQuery1000000-16     3927444457     2844597499     -27.57%

benchmark                         old allocs     new allocs     delta
BenchmarkRangeQuery100000-16      49956          3518           -92.96%
BenchmarkRangeQuery200000-16      204431         9820           -95.20%
BenchmarkRangeQuery500000-16      13413890       4135290        -69.17%
BenchmarkRangeQuery1000000-16     26830056       8268585        -69.18%

benchmark                         old bytes      new bytes     delta
BenchmarkRangeQuery100000-16      1808878        321027        -82.25%
BenchmarkRangeQuery200000-16      9968806        719492        -92.78%
BenchmarkRangeQuery500000-16      822888736      262896816     -68.05%
BenchmarkRangeQuery1000000-16     1646616496     526540984     -68.02%

I'm also fixing the storage benchmark that is currently crashing because of a change in the limits.

[slim-bean]

Nice LGTM!