Refactored and completed Path; added query to Chain trait; refactored query code into TendermintChain

[greg-szabo]

Closes: #157
Closes: #172
Closes: #173

Description

Apologies for the monstre changes again, but the changes are unfortunately dependent on each other.

• Refactored Path into an enum, implemented all paths. Result is a smaller codebase.
• Paths now know if they are in the provableStore or not and a check was added to the query to not try to prove something in the privateStore.
• Implemented query in line with ADR: Domain Decomposition #162 : Chain trait and TendermintChain. This gives us (somewhat) a template on how to implement subscription and transactions. At least it helped me understand the necessities, so I can start working on those in the relayer.
• Deleted a bunch more obsolete code, where I could.

Tests are lacking, but maybe soon, in another issue. (Local execution worked.)

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For contributor use:

• Unit tests written
• Added test to CI if applicable
• Updated CHANGELOG_PENDING.md
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation (docs/) and code comments
• Re-reviewed Files changed in the Github PR explorer

[romac]

Great stuff! Left a few suggestions for future consideration but nothing blocking the merge :)

[codecov-commenter]

Codecov Report

Merging #174 into master will increase coverage by 1.9%.
The diff coverage is 19.9%.

@@           Coverage Diff            @@
##           master    #174     +/-   ##
========================================
+ Coverage    13.6%   15.6%   +1.9%     
========================================
  Files          69      58     -11     
  Lines        3752    3720     -32     
  Branches     1374    1429     +55     
========================================
+ Hits          513     582     +69     
+ Misses       2618    2430    -188     
- Partials      621     708     +87     

Impacted Files	Coverage Δ
modules/src/events.rs	0.0% <ø> (ø)
modules/src/ics02_client/client_type.rs	47.6% <ø> (ø)
modules/src/ics03_connection/error.rs	25.0% <0.0%> (-8.4%)	⬇️
modules/src/ics03_connection/exported.rs	42.1% <0.0%> (-9.6%)	⬇️
modules/src/ics04_channel/error.rs	23.0% <0.0%> (-2.0%)	⬇️
modules/src/ics04_channel/packet.rs	0.0% <0.0%> (ø)
modules/src/ics07_tendermint/error.rs	33.3% <0.0%> (+33.3%)	⬆️
modules/src/ics07_tendermint/msgs/create_client.rs	0.0% <0.0%> (ø)
modules/src/ics23_commitment/mod.rs	0.0% <0.0%> (ø)
modules/src/ics24_host/path.rs	0.0% <0.0%> (ø)
... and 41 more

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