Simplify Indexer Service

[marcus-snx]

There is now only 1 indexer service: indexer-v2. To start indexing, run the service using docker compose and specify a network and config:

docker compose run indexer-v2 --network_name base_mainnet --config_name synthetix-v3

An optional list of --contract_names can also be provided to index only these contracts from the config:

docker compose run indexer-v2 --network_name base_mainnet --config_name synthetix-v3 --contract_names CoreProxy,MarketProxy

Other changes:

• add Arbitrum curve USDx/USDe pool to config to showcase external data indexing
• stringify all hex addresses in yaml configs as sometimes the python parser is converting these values to dec
• simplify the subsquid patching to use internal data to get the latest block to index