Add extended community field, use in dataplane

[progwriter]

No description provided.

[batfish-bot]

This change is 

[arifogel]

Reviewed 11 of 11 files at r1.
Reviewable status: complete! all files reviewed, all discussions resolved

[codecov]

Codecov Report

Merging #4193 into master will decrease coverage by 0.01%.
The diff coverage is 94.59%.

@@             Coverage Diff              @@
##             master    #4193      +/-   ##
============================================
- Coverage     75.36%   75.34%   -0.02%     
+ Complexity    25367    24997     -370     
============================================
  Files          2046     2046              
  Lines        100804    99789    -1015     
  Branches      12079    11865     -214     
============================================
- Hits          75971    75190     -781     
+ Misses        19403    19216     -187     
+ Partials       5430     5383      -47

Impacted Files	Coverage Δ	Complexity Δ
.../src/main/java/org/batfish/datamodel/BgpRoute.java	87.39% <100%> (+1.41%)	24 <2> (+2)	⬆️
...h/representation/juniper/JuniperConfiguration.java	89.26% <100%> (ø)	377 <0> (ø)	⬇️
...presentation/cumulus/CumulusNcluConfiguration.java	95.72% <100%> (+0.04%)	140 <0> (ø)	⬇️
...batfish/dataplane/protocols/BgpProtocolHelper.java	94.69% <83.33%> (-0.81%)	37 <0> (+1)
...tfish/datamodel/bgp/AddressFamilyCapabilities.java	89.65% <90%> (-0.22%)	26 <2> (+2)
...atfish/datamodel/answers/InputValidationUtils.java	48.14% <0%> (-11.12%)	8% <0%> (-5%)
...tamodel/questions/BgpProcessPropertySpecifier.java	86.48% <0%> (-10.29%)	7% <0%> (-4%)
...del/questions/NamedStructurePropertySpecifier.java	87.87% <0%> (-9.56%)	4% <0%> (-2%)
.../datamodel/questions/BgpPeerPropertySpecifier.java	84% <0%> (-7.57%)	16% <0%> (-7%)
...h/specifier/parboiled/ParboiledInputValidator.java	74.62% <0%> (-7.47%)	10% <0%> (-1%)
... and 15 more