Add support for multiple substrate urls

[sameh-farouk]

• Add support for multiple substrate URLs for redundancy
  - related issues
  Support multiple substrate URLs #31

[sameh-farouk]

Tested with this TFCHAIN_WS_PROVIDER_URL value

TFCHAIN_WS_PROVIDER_URL=wss://tfchain.down.grid.tf,wss://tfchain.02.grid.tf

Logs:

tf_kyc_api  | {"time":"2025-01-21T11:31:44.835499003Z","level":"DEBUG","msg":"Setting up services"}
tf_kyc_api  | {"level":"debug","url":"wss://tfchain.down.grid.tf","time":"2025-01-21T11:31:44Z","message":"connecting"}
tf_kyc_api  | 2025/01/21 11:31:44 Connecting to wss://tfchain.down.grid.tf...
tf_kyc_api  | {"level":"error","error":"error connecting to substrate at 'wss://tfchain.down.grid.tf': remote error: tls: internal error","time":"2025-01-21T11:31:44Z","message":"failed to connect to endpoint, retrying"}
tf_kyc_api  | {"level":"debug","url":"wss://tfchain.02.grid.tf","time":"2025-01-21T11:31:45Z","message":"connecting"}
tf_kyc_api  | 2025/01/21 11:31:45 Connecting to wss://tfchain.02.grid.tf...
tf_kyc_api  | {"time":"2025-01-21T11:31:45.257056964Z","level":"DEBUG","msg":"Setting up routes"}