Better error reporting on bad enr in --bootnodes

[dapplion]

Describe the bug

Running lodestar with --bootnodes=bad_enr results in

Sep-08 15:43:14.426[]                 info: Initializing beacon state from anchor state slot=0, epoch=0, stateRoot=0xea2855c3a4d341cfc991dcfc3d685347b0a69dbe63b51f1d838248e4cbfa0c1e
 ✖ Error: string encoded ENR must start with 'enr:'
    at Function.decodeTxt (/usr/app/node_modules/@chainsafe/discv5/lib/enr/enr.js:92:19)
    at createNodeJsLibp2p (file:///usr/app/packages/beacon-node/src/network/nodejs/util.ts:56:54)
    at Object.beaconHandler [as handler] (file:///usr/app/packages/cli/src/cmds/beacon/handler.ts:74:15)

It's hard to figure out that the cause of the error is a bad enr.

Expected behavior

Throw early and with a message: bad ENR formatting supplied as bootnode.

[nazarhussain]

We have updated a proper message and fail earlier during the command parsing. This applies to both beacon and bootnode commands.

lodestar/packages/cli/src/options/beaconNodeOptions/network.ts

Line 119 in 6ac8c07

throw new YargsError(`Provided ENR in bootnodes is invalid:\n ${enrStr}`);