```
Change gui code to use gArgs, Params() functions directly instead of
going through interfaces::Node.
Remotely accessing bitcoin-node ArgsManager from bitcoin-gui works fine
in https://github.com/bitcoin/bitcoin/pull/10102, when bitcoin-gui
spawns a new bitcoin-node process and controls its startup, but for
bitcoin-gui to support -ipcconnect option in
https://github.com/bitcoin/bitcoin/pull/19461 and connect to an existing
bitcoin-node process, it needs ability to parse arguments itself before
connecting out.
This change also simplifies
https://github.com/bitcoin/bitcoin/pull/10102 a bit, by making the
bitcoin-gui -> bitcoin-node startup sequence more similar to the
bitcoin-node -> bitcoin-wallet startup sequence where the parent process
parses arguments and passes them to the child process instead of the
parent process using the child process to parse arguments.
```
Partial backport (1/4) of bitcoin-core/gui PR35:
https://github.com/bitcoin-core/gui/pull/35/commits/91aced7c7e6e75c1f5896b7e3843015177f32748
Depends on D8651.