Migrate API v2 endpoints

[franzns]

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

• Pools list fetching - /pools/
  • Used by Frontend - pools table
• Single pool fetching - /pools//poolId
  • Used by frontend - single pool page
• SOR - /sor #580
  • Used by Cowswap
  • Moving to beets API once SORv2 is implemented there
• Order - /order #574
  • Maybe Used by Cowswap? (unsure if they ever switched to it)
  • Could move to beets API eventually after SOR
• Tokens - /tokens #579
  • Not used by any services
• /check-wallet #575
  • Used by the frontend to check if wallet is flagged by TRM
• /tenderly #576
  • Was used by SDK, No longer used
• /hal #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
• /defender #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.

[franzns]

Tokens, Pool list and single pool fetching supported by api v3