Make ZetaClient more performant and reliable

[lumtis]

Creating a new EPIC to make this one focused on code structure and testing: #1611

This EPIC focus on ZetaClient performance, better ability to handle errors and improving configuration, documentation of its usage

Tasks

Beta Give feedback

1. zetaclientd support for multiple RPCs per chain w/ failover #1417
   zetaclient +1
   
2. Support hostname in addition to public IP for zetaclient #1038
   zetaclient +1
3. observer get-tss-address - is poorly documented #1624
   docs zetaclient +2
4. A more reliable rescan mechanism for inbound tx observation to avoid missing votes #1737
   zetaclient +1
   
5. ZetaClient should have no chain when initialized #1901
   zetaclient +1
6. MYIP Env Var should not override the zetaclient_config file or be required #1621
   zetaclient +1
7. ZetaClient priority coverage #2028
   test zetaclient +2
8. Make Bitcoin client chain agnostic #2030
   zetaclient +1
9. To improve the accuracy of Bitcoin gas estimator, some research work can be done on 3rd party gas estimators #2087
   chain:bitcoin zetaclient +2
   
10. Unify chainParams, signer, and observers lifecycle #2519
    code-quality refactor zetaclient +3