Merge branch 'graphite-seriesbytag' of https://github.com/alexanderzobnin/grafana into graphite-series-by-tags

fix: Html escaping caused issue in InfluxDB query editor,  could not pick greater than or less then operators, fixes #9871

Adds dependencies for node-gyp to the building from source
docs page. ref #9861

Fixes #9790

* fix cloudwatch ec2_instance_attribute

* add test

* minor fix

graph: the stack & legend sort sync was not working correctly, the z-index sorting that happened in after the legend sort order was applied and messed with the order even though the sort function returned zero for all entries, combined the sort function to one sort function, fixes #9789 (#9797)

Add AWS/NetworkELB to cloudwatch definitions

(cloudwatch) fix query inspector

(cloudwatch) return empty array for no datapoints

MySQL Performance when using GF_DATABASE_URL

Use hex.EncodeToString to encode to hex

Using the EncodeToString function from the encoding/hex package
is much faster than calling the fmt.Sprintf with %x

Benchmark results below with the following code

func BenchmarkHexPrint(b *testing.B) {
  data := []byte("hellothere")
  for n := 0; n < b.N; n++ {
    // _ = fmt.Sprintf("%x", data)
    _ = hex.EncodeToString(data)
  }
}

name        old time/op    new time/op    delta
HexPrint-4     188ns ± 1%      99ns ± 1%  -47.40%  (p=0.008 n=5+5)

name        old alloc/op   new alloc/op   delta
HexPrint-4     64.0B ± 0%     64.0B ± 0%     ~     (all equal)

name        old allocs/op  new allocs/op  delta
HexPrint-4      2.00 ± 0%      2.00 ± 0%     ~     (all equal)