Remove ALERTS_URL and CHIA_ALERTS_PUBKEY

[Rigidity]

These config items are confusing and also not used anywhere in either chia-blockchain or chia-blockchain-gui, and the only reference within the org are other config files including them.

It seems after looking at the source code of chia-blockchain==1.0.0, we used to make an API call to this endpoint, parse the JSON, and use this as a source of truth for the GENESIS_CHALLENGE.

However, this is now ConsensusConstants.GENESIS_CHALLENGE, and an API call is no longer used anywhere for this.

[hoffmang9]

These are vestigial and were part of the fair launch process that occurred on March 19, 2021

[Rigidity]

These are vestigial and were part of the fair launch process that occurred on March 19, 2021

I think it would be cool to preserve this message standalone in the CLI and/or GUI:

Operational error causes Fed payment system to crash
We stand on the shoulders of giants, now let's get farming!

But if these config items aren't used in the code (nor do we plan to, since it shouldn't need to phone home for the genesis challenge anymore), imo they should be removed.

Not going to die on this hill though, so if it's worth keeping around to anyone, sure