Replace oasis-node with Oasis CLI in Run Node chapter

[matevz]

Followup to #399

There will always be:

1. oasis-node specific features (i.e. running the actual node)
2. Oasis CLI specific features or features that oasis-node shouldn't be used anymore for (e.g. wallets, addressbook, ParaTime specific txes, hw wallet)
3. common features (i.e. node status)

Run grep -R "oasis-node" docs/node and figure out which of the groups above would an action fall into.

Then, for each group above:

1. leave oasis-node specific ones alone (perhaps revamp the $ADDR and other env variables)
2. rewrite oasis-node command to Oasis CLI
3. for features that are and will remain common to both tools, use a Tab view with both options (something like yarn vs npm vs pnpm)

[matevz]

Oasis Core 23.0 (#5376) removed some subcommands relevant to this chapter.

[matevz]

For now, let's update the Running your Validator node docs, by:

1. create the entity by running oasis acc entity init using the account in your Oasis CLI wallet Add oasis account entity init cli#154 (btw. perhaps oasis acc entity get would also be useful which fetches the existing entity descriptor from the registry, if it exists?)
2. run oasis-node with the new entity.json
3. once the node is connect, get node ID: oasis-node control status -a unix:/serverdir/internal.sock | jq .identity.node -r
4. adjust the entity.json file and add

"nodes": [
    "YOUR_PUBLIC_KEY_HERE"
  ]

6. run oasis acc entity register command passing the new entity.json