gnosis / dex-services / 4475

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Implement token price estimation in pricegraph (#1183)

This PR implements token price estimation in `pricegraph`. Additionally this PR modifies the `historic_prices` E2E script to use this method instead of the bid ask spread. This significantly modifies what the E2E script was testing, so a new E2E script has been introduced in #1218 to produce a more valuable metric to the one that previously existed.

Regarding the imprecision, the average error of the price estimate is 28000x :warning: (mostly because of some large outliers and non-liquid tokens). In recent batches for a token like WETH this is down to around 4% since the orderbook is more dense and therefore the estimates are much more accurate. Note that the previous promising analysis on price accuracy was using a different mechanism to estimate **exchange rates** between tokens and not token prices (in OWL reference token). 

### Test Plan

New unit tests in `pricegraph`, e2e historic prices now uses the new estimation API:
```
cargo run --release -p e2e --bin historic_prices -- --orderbook-file target/orderbook-file-mainnet
   Compiling e2e v1.0.0 (/var/home/nlordell/Developer/dex-services/e2e)
    Finished release [optimized] target(s) in 2.82s
     Running `target/release/historic_prices --orderbook-file target/orderbook-file-mainnet`
54285 / 54285 [===============================================] 100.00 % 222.25/s
Processed 13200 token prices: bad estimates 46.73%, average error 28770.95%.
```

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