Implement fee recipient API

[pablomendezroyo]

Implement the Fee recipient API to allow setting different addresses for each pubkey, also implement a switch button to set the same one for all of them.

• [x] Make sure all the clients support this feature (this UI is cross-client compatible): @tropicar
  • [x] Check if all 4 clients implement the /feerecipient endpoint
  • [x] Check if it is possible to perform the requests from the UI (via test)
  • [x] Check if CORS is configured to allow these requests from the browser
• [ ] Implement input for the fee recipient address with the following features:
  • It will be a mandatory value
  • [ ] front
  • Use a regex for the address
  • [ ] back
  • [x] front
  • Switch the button for "all"
  • [ ] back
  • [ ] front
  • New column for the fee recipient address
  • [ ] back
  • [ ] front

[tropicar]

The fee recipient must be mandatory, by default the client assigns the burnout value instead. In my opinion.

[dsimog01]

All clients support GET/POST requests to .../feerecipient endpoint

[dsimog01]

The METHOD_NOT_ALLOWED error was shown because the header "Content-type:application/json" was missing.

[dsimog01]

Check /feerecipient for all consensus clients:	Tables	Postman GET	Postman POST	TS Test GET	TS Test POST	Browser GET	Browser POST
Prysm	OK	OK	OK	OK	CORS	CORS
Teku	OK	OK	OK	OK	CORS	CORS
Nimbus	OK	OK	OK	OK	CORS	CORS
Lighthouse	OK	OK	OK	OK	OK	Error

In order to perform the GET/POST requests to Teku, it is necessary to include a .p12 certificate and passphrase. The module "axios" is required for this task

[dsimog01]

To read the .p12 certificate, the code must not be executed in the browser. Moreover, there are CORS politics that block requests from the browser.

To solve this, a proxy server can be a feasible alternative.

[dsimog01]

Performing GET/POST /feerecipient through the proxy server via browser:

X	GET	POST
Prysm	OK	OK
Teku	OK	OK
Nimbus	OK	OK
Lighthouse	OK	OK

Note that Teku does not allow to set the burn address (0x00..00) via its API. This must be taken into account