Reintroduce RPC query parsing

[thanethomson]

Closes #859

rust-peg had a release in April that solved some of the original issues we had with this. This PR is mostly just a copy/paste from #858.

• Referenced an issue explaining the need for the change
• Updated all relevant documentation in docs
• Updated all code comments where relevant
• Wrote tests
• Added entry in .changelog/

[codecov-commenter]

Codecov Report

Merging #949 (8c5e9f6) into master (b3cd0b7) will increase coverage by 0.2%.
The diff coverage is 84.4%.

@@           Coverage Diff            @@
##           master    #949     +/-   ##
========================================
+ Coverage    71.6%   71.9%   +0.2%     
========================================
  Files         203     203             
  Lines       16277   16550    +273     
========================================
+ Hits        11669   11911    +242     
- Misses       4608    4639     +31     

Impacted Files	Coverage Δ
rpc/src/client/bin/main.rs	0.6% <0.0%> (-0.2%)	⬇️
rpc/src/query.rs	88.5% <97.0%> (+10.3%)	⬆️
rpc/src/endpoint/commit.rs	40.0% <0.0%> (-60.0%)	⬇️
rpc/src/endpoint/genesis.rs	40.0% <0.0%> (-60.0%)	⬇️
light-client/src/types.rs	29.2% <0.0%> (-0.3%)	⬇️
rpc/src/method.rs	28.8% <0.0%> (+0.2%)	⬆️
tendermint/src/node.rs	66.1% <0.0%> (+0.2%)	⬆️
tendermint/src/timeout.rs	84.9% <0.0%> (+1.8%)	⬆️
tendermint/src/signature.rs	60.5% <0.0%> (+4.1%)	⬆️

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[andynog]

Tested the subscribe with NewBlock events and seems to work correctly

[xla]

utACK

✔️ 👛 🎿 ⛰

[thanethomson]

Sorry @xla, had to fix a minor merge conflict. See 8c5e9f6

[xla]

✨ ⏫ 🍽 💢