Finish typing cleanup for CLI params

[acolytec3]

Our client CLI params is currently @ts-ignored because of at least 2 issues related to how yargs parses params that are configured with array: true.

Both bootnodes and transports are currently defined as being array params and yargs parses these as a type (string | number)[] | undefined.

In the case of transports, it really doesn't even make sense to have this as an array since we only support rlpx. We should rework this option so that it is a simple boolean param and starts up an RLPXServer inside client/src/config.ts if this param isn't passed (or is passed as true) and start the client with no servers if --transports=false is passed.

In both cases, the typing should be cleaned up and we ensure we can remove this @ts-ignore without Typescript complaining about type mismatches.

[holgerd77]

Then rename to --networking or otherwise plain ---rlpx (maybe networking is easier, guess there are a lot of people who are not so firm with networking topology) might be a more intuitive version.

[acolytec3]

The transports part of this was dealt with in #3069