feat: add hand-written Prometheus remote write request parser (#1628)

## Rationale

A hand-written remote write request parser to replace prost, with the
primary goal of achieving zero-allocation parsing.

## Detailed Changes

- The new `remote_write` directory contains the core implementation of
the hand-written parser.

- Add benchmarks.

- Add a .proto file in `pb_types`.

- Fix CI errors.

## Test Plan

- Unit tests can be found at the end of the `pb_reader.rs`.

- A comprehensive equivalence test is available in
`equivalence_test.rs`, which validates the correctness of the
hand-written parser by comparing its output with that of the prost
auto-generated parser.

Author: BaldDemian

.github/workflows/ci.yml

@@ -61,6 +61,7 @@ jobs:
         run: |
           sudo apt update
           sudo apt install --yes protobuf-compiler
+          cargo install pb-rs
       - name: Install check binaries
         run: |
           cargo install --git https://github.com/DevinR528/cargo-sort --rev 55ec890 --locked
@@ -82,6 +83,7 @@ jobs:
         run: |
           sudo apt update
           sudo apt install --yes protobuf-compiler
+          cargo install pb-rs
       - uses: Swatinem/rust-cache@v2
       - name: Run Unit Tests
         run: |

.gitignore

@@ -9,5 +9,6 @@ integration_tests/dist_query/output
 .project
 .tools
 bin
+!src/benchmarks/src/bin
 coverage.txt
 tini