No API changes, merely changes the import path.

Rework the implementation of event query parsing and execution to
improve performance and reduce memory usage.

Previous memory and CPU profiles of the pubsub service showed query
processing as a significant hotspot. While we don't have evidence that
this is visibly hurting users, fixing it is fairly easy and self-contained.

Updates #6439.

Typical benchmark results comparing the original implementation (PEG) with the reworked implementation (Custom):
```
TEST                        TIME/OP  BYTES/OP  ALLOCS/OP  SPEEDUP   MEM SAVING
BenchmarkParsePEG-12       51716 ns  526832    27
BenchmarkParseCustom-12     2167 ns    4616    17         23.8x     99.1%
BenchmarkMatchPEG-12        3086 ns    1097    22
BenchmarkMatchCustom-12    294.2 ns      64     3         10.5x     94.1%
```

Components:
* Add a basic parsing benchmark.
* Move the original query implementation to a subdirectory.
* Add lexical scanner for Query expressions.
* Add a parser for Query expressions.
* Implement query compiler.
* Add test cases based on OpenAPI examples.
* Add MustCompile to replace the original MustParse, and update usage.

Co-authored-by: Callum Waters <cmwaters19@gmail.com>
Co-authored-by: M. J. Fromberger <fromberger@interchain.io>

Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>

The PR added a new field `index` to event attribute, that will cause indexer service to index the event if set to true.

* format: add format cmd & goimport repo

- replaced format command
- added goimports to format command
- ran goimports

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* fix outliers & undo proto file changes

* libs/common: Refactor libs/common 01

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* regenerate proto files, move intslice to where its used

* update kv.KVPair(s) to kv.Pair(s)

* add changelog entry

* make intInSlice private

* Rename Tag(s) to Event(s)

- tag was replaced with event, but in some places it still mentions tag, would be easier to understand if we tried to replace it with event to not confuse people.

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* more  changes from tag -> event

* rename events to compositeKeys and keys

* Apply suggestions from code review

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* add minor documentation on how composite keys are constructed

* rename eventkey to compositekey

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* add changelog entry & add info to regenerate confid to changelog entry

- Replace the previous intersect call, which was called at each query condition, with a map intersection.
- Replace fmt.Sprintf with string()

closes: #3076

Benchmarks

```
Old
goos: darwin
goarch: amd64
pkg: github.com/tendermint/tendermint/state/txindex/kv
BenchmarkTxSearch-4   	     200	 103641206 ns/op	 7998416 B/op	   71171 allocs/op
PASS
ok  	github.com/tendermint/tendermint/state/txindex/kv	26.019s

New
goos: darwin
goarch: amd64
pkg: github.com/tendermint/tendermint/state/txindex/kv
BenchmarkTxSearch-4   	    1000	  38615024 ns/op	13515226 B/op	  166460 allocs/op
PASS
ok  	github.com/tendermint/tendermint/state/txindex/kv	53.618s
```

~62% performance improvement

Commits:

* Refactor tx search

* Add pending changelog entry

* Add tx search benchmarking

* remove intermediate hashes list

also reset timer in BenchmarkTxSearch
and fix other benchmark

* fix import

* Add test cases

* Fix searching

* Replace fmt.Sprintf with string

* Update state/txindex/kv/kv.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Rename params

* Cleanup

* Check error in benchmarks