feat: Create new proxy service to store (and relay) broadcasted daft data

[raunakab]

Overview

This PR introduces a new Rust proxy-service which captures metrics outputted by Daft, and exposes a simple HTTP endpoint for a dashboard to hit to query that data.

Usage

# Terminal 1:
cd dashboard/proxy-service
cargo run

# Terminal 2:
# Create a new test.py file and put some code that uses Daft in there.
# Make sure it executes the query (by calling `.collect()` or something similar).
# Then, run it.
python test.py

# The proxy-service should have caught it and stored it.
# Test that it did by running the following:
curl http://localhost:3239

# You should see a (non-empty) JSON array being printed out.

[codspeed-hq]

CodSpeed Performance Report

Merging #3774 will improve performances by 99.98%

_{Comparing proxy-service (c1a4c71) with main (86adc44)}

Summary

⚡ 2 improvements
✅ 25 untouched benchmarks

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
⚡	test_iter_rows_first_row[100 Small Files]	342.5 ms	171.3 ms	+99.98%
⚡	test_show[100 Small Files]	24.2 ms	16.4 ms	+47.65%