Migrate API v2 endpoints

Following endpoints are available on api.balancer.fi which need to be migrated:

[x] Pools list fetching - /pools/
- Used by Frontend - pools table
[x] Single pool fetching - /pools/
/poolId
- Used by frontend - single pool page
[ ] #580
- Used by Cowswap
- Moving to beets API once SORv2 is implemented there
[ ] #574
- Maybe Used by Cowswap? (unsure if they ever switched to it)
- Could move to beets API eventually after SOR
[x] #579
- Not used by any services
[ ] #575
- Used by the frontend to check if wallet is flagged by TRM
[ ] #576
- Was used by SDK, No longer used
[ ] #577
- Picks up new pool creations on Ethereum/Polygon/Arbitrum/Gnosis and creates a PR to allowlist it on Frontend, and allowlist tokens in Tokenlists repo
[ ] #578
- Same as /hal but works for Base and Avalanche too (so 6 chains total), both webhooks always run but they create the same PR with same details so it's ok if both run.

beethovenxfi / beethovenx-backend