Clean up unused network parameter: revocationDelay

[pinheadmz]

This network names parameter has been replaced since mainnet launch, I do not think it is used anywhere in the code and can probably be removed for developer sanity and confusion's sake:

https://github.com/handshake-org/hsd/blob/c861e4fc95f0d023a7da4c90b93dab692b9209d0/lib/protocol/networks.js#L335-L341

[pinheadmz]

Another thing we don't use any more is the entire hard-coded ICANN root zone. These files:

lib/dns/icann.js
lib/dns/icann-browser.js
lib/dns/tld.db
lib/dns/tld.json

I suspect hsd used to be built like hnsd with a hard-coded ICANN root zone but before mainnet launch, the hsd root server switched to actually resolving root zone names using a bns RootResolver with hard-coded hints instead.

This commit message implies the icann stuff was designed to be a hard-coded fallback, so maybe we don't need to remove the files but just integrate the trigger to use them in the right scenario.

[rithvikvibhu]

another cleanup: https://github.com/handshake-org/hsd/blob/81bddcd2f9215c271d0d01f5655ccd836e864475/lib/node/spvnode.js#L76

selfish was removed and this option doesn't do anything. Must also be removed from https://hsd-dev.org/guides/config.html