[x/config] Deprecate src/x/config/listenaddress

[andrewmains12]

What this PR does / why we need it: Given #2016, we no longer need a homebrew means of resolving ports from the environment. Users who want this functionality can now do:

listenAddress:
   value: 0.0.0.0:${MY_PORT}

Given sufficient documentation (hopefully provided), this is imo simpler and easier to grok behavior-wise than the homebrewed solution we were using before.

The change should be backwards compatible; anyone using type: environment will still have their
or

listenAddress:
   value: ${MY_ADRR}:${MY_PORT}

Special notes for your reviewer:

Does this PR introduce a user-facing and/or backwards incompatible change?:

Port/host environment resolution for query and m3collector configs can now be done using config environment interpolation in go.uber.org/config (see config/README.md for
details). Instead of:

    listenAddress:
      type: environment
      envVarListenPort: MY_PORT_VAR

 one can do:

    listenAddress:
      value: 0.0.0.0:${MY_PORT_VAR}

The old mechanism will continue to work, but will log a deprecation notice.

Does this PR require updating code package or user-facing documentation?:

Updated listenaddress package documentation with the deprecation notice.

[mway]

we will load -> the interpolated YAML will be:

[codecov]

Codecov Report

Merging #2017 into master will decrease coverage by 3.3%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #2017     +/-   ##
=========================================
- Coverage    63.1%    59.7%   -3.4%     
=========================================
  Files        1079     1105     +26     
  Lines      105667   104676    -991     
=========================================
- Hits        66679    62519   -4160     
- Misses      34816    37970   +3154     
- Partials     4172     4187     +15

Flag	Coverage Δ
#aggregator	66.1% <ø> (+11.7%)	⬆️
#cluster	55.3% <ø> (-4.8%)	⬇️
#collector	8.9% <ø> (-41.6%)	⬇️
#dbnode	61.9% <ø> (+0.2%)	⬆️
#m3em	60.9% <ø> (+26.4%)	⬆️
#m3ninx	54.5% <ø> (-3%)	⬇️
#m3nsch	51.1% <ø> (ø)	⬆️
#metrics	21.7% <ø> (-31.2%)	⬇️
#msg	72.9% <ø> (+28.1%)	⬆️
#query	57% <ø> (-10.2%)	⬇️
#x	61.7% <100%> (-2.6%)	⬇️

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