Update NN Setup Doc (WIP)

[smk762]

Work in progress, awaiting some 3P nodes to update before updating commit hash etc - set to master for now.

• updated BTC to LTC
• updated PBC to SFUSD
• added some deps required to build on 20.04

No need to merge yet - can refer next season ops to https://smk762.github.io/developer-docs/notary/setup-Komodo-Notary-Node.html while doc is being finalised.

[smk762]

@gcharang @tonymorony please review and merge - I'll PR any pending 3P commit hash / branch updates as they come in.

[gcharang]

LGTM!