Improved Sources and max_data_age

[0xSpuddy]

This pull request hardens all custom spot price median feeds with more sources, and also makes the daemon more efficient when making api / rpc requests. Care was taken to make sure the reporter's configs are more "production ready" when they generate.

Various Improvements:

• The Curve api has been tested with reporterd is now used by default for some custom feeds.
• Methods tested and implemented for getting price data from uniswap subgraphs when derivedETH method is not available.
• Additional methods added for getting osmosis pool data so the USDN/USD feed now has 3 sources by default.

This pull request addresses the following issues:

• PriceGuard - block submits when the value returned by the api is too old #5 max data age added as configurable for each custom feed source (MaxPriceAge was already there for the indexPriceCache)
• Derive the chain id from the node #4 Chain id is now determined automatically. --chain-id flag removed