feat!: unified DedotClient interface

[sinzii]

This PR is a big work to revamping the DedotClient interface as a unified interface for both legacy or new JSON PRC specs. There will be some breaking changes on the interface but most of the features will work as it was before.

Now we only have one DedotClient interface for both legacy & new JSON RPC specs:

// via new JSON-RPC specs, default
const client = DedotClient.new(new WsProvider('wss://...'));

// via legacy JSON-RPC specs
const client = DedotClient.legacy(new WsProvider('wss://...'));

// or
const client = DedotClient.new({ provider: new WsProvider('wss://...'), rpcVersion: 'legacy' });