[query] Add latency metrics to remote reads

[arnikola]

What this PR does / why we need it:
Adds metrics for latency on the remote read path

[codecov]

Codecov Report

Merging #2027 into master will decrease coverage by 6.1%.
The diff coverage is 88.8%.

@@           Coverage Diff            @@
##           master   #2027     +/-   ##
========================================
- Coverage    71.9%   65.7%   -6.2%     
========================================
  Files         971    1000     +29     
  Lines       84655   85826   +1171     
========================================
- Hits        60913   56466   -4447     
- Misses      19678   25336   +5658     
+ Partials     4064    4024     -40

Flag	Coverage Δ
#aggregator	45.4% <ø> (-19.4%)	⬇️
#cluster	59.4% <ø> (-26.1%)	⬇️
#collector	54.9% <ø> (ø)	⬆️
#dbnode	76.7% <ø> (+6.7%)	⬆️
#m3em	32.5% <0%> (-25.3%)	⬇️
#m3ninx	60.6% <ø> (-7.5%)	⬇️
#m3nsch	60.5% <ø> (-9.5%)	⬇️
#metrics	53.8% <ø> (+36%)	⬆️
#msg	74.9% <ø> (+0.1%)	⬆️
#query	54.4% <88.8%> (+15.2%)	⬆️
#x	84% <ø> (+8.9%)	⬆️

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[robskillington]

LGTM