Node runner guide

[damip]

The priority is docs/node/initial.mdx which is the doc for initial node runners (not normal ones who have their own doc in the rest of docs/node/* !).

TODO for initial node runners:

• [x] fill the TODOs on how to import saved wallets
• [x] add node routability setup at node install phase. Insist that without routability, their node will be unstable through lack of connectivity
  • [x] for routability, DO NOT FORGET TO SET THE IP ADDRESS IN THE CONFIG
  • [x] tell how to check that it is defined (eg. I think the client tells you your IP address on top of get_info (?))
• [x] check that all links work
• [x] try to render and see how it looks
• [x] add a last phase where you check the status of your node:
  • [x] routability check using an external service like https://portchecker.co/
  • [x] make sure the node staking address is the one in the initial rolls file
  • [x] make sure your node is connected to peers