add cosmos.directory provider

[gluckzhang]

cosmos.directory provides super nice APIs for checking a chain's information, for example: https://chains.cosmos.directory/ and https://chains.cosmos.directory/babylon We may consider adding a provider that ultilzies these endpoints and query a chain's parameters.

Pros:

• easier to get chain params like community tax, calculated APR, bank denom, etc.
• we can use the RPC proxy provided by cosmos.directory
• the config file will be further optimized, maybe something like the following:

chains:
  "BabylonMainnet":
    chain_id: bbn-1
    valoper_address: xxx
    provider:
      name: cosmos.directory

Cons:

• this is one more dependency and we cannot guarantee that the cosmos.directory APIs always work
• cosmos.directory only provides chains information in mainnet

As an alternative, we save the response as a static json file here: https://github.com/Firstset/tenderduty/tree/main/static and update it regularly. We only need the basic information like community_tax, calculated_apr, bank_denom, etc. which do not change frequently.