feat/Interact directly with the pool in Uniswap connector

[VPashkov]

Before submitting this PR, please make sure:

• Your code builds clean without any errors or warnings
• You are using approved title ("feat/", "fix/", "docs/", "refactor/")

A description of the changes proposed in the pull request:
Adds the ability to use Quoter rather than Smart Order Router to the Uniswap connector as an option.
To achieve this uniswap.yml config file is extended with the following:

• useRouter (bool, default=true) - if True, estimation and execution functions use the Router; if false, use quote and trade functions of SDK.
• feeTier (string, default='MEDIUM') - Matches one of the Uniswap fee tier strings. If useRouter is False, then the user has to specify feeTier to find the right pool.
• uniswapV3QuoterV2ContractAddress (string) - a variable added to each network in contractAddresses section. Stores the address of Uniswap Quoter V2. It can be found here https://docs.uniswap.org/contracts/v3/reference/deployments.

Tests performed by the developer:

• Requests to get price and to execute trade sent using examples from test-helpers/curl/curl.sh. E.g.:

curl -s -X POST -k --key $GATEWAY_KEY --cert $GATEWAY_CERT -H "Content-Type: application/json" -d "$(envsubst < ./test-helpers/curl/requests/price_uniswap.json)" https://localhost:15888/amm/price | jq

• Checked that prices returned by the Quoter are the same(or very close) as those returned by the Router when using the same fee tier.
• Checked that executing trades(/amm/trade) works with the Quoter.

Tips for QA testing:

• Sometimes price returned using the Router is different than using the Quoter. This is usually due to a different fee tier. Try a different value for feeTier variable in uniswap.yml config file to get the same price.

[VPashkov]

Resolves #112

[toxicehc]

Hi @VPashkov , how would I test this on a HB/gateway instance running from source? The production version of the gateway is no longer able to get prices from Uniswap as of some days ago..

[fengtality]

LGTM

• Reviewed code - looks clean
• Tested on Goerli - buy and sell trades worked
• Ran tests successfully

Thanks for the contribution!

[emusol]

Hey this seems to not solve the LP side of uniswap, maybe similar udpate to the code can help?

[nikspz]

#152 Created issue for UniswapLP