feat: Add account entity init docs and examples

docs/account.md

@@ -519,6 +519,30 @@ transaction.
 
 ### Entity Management {#entity}
 
+#### Initialize Entity {#entity-init}
+
+When setting up a validator node for the first time, you will need to provide
+the path to the file containing your entity descriptor in your Oasis node config
+as well as register it in the network registry. Use `account entity init` to
+generate the entity descriptor file containing the public key of the selected
+account.
+
+![code shell](../examples/account/entity-init.in.static)
+
+![code](../examples/account/entity-init.out.static)
+
+By default, the file content will be printed to the standard output. You can use
+`-o` parameter to store it to a file, for example:
+
+![code shell](../examples/account/entity-init-o.y.in)
+
+:::info
+
+[Account](#account) selector is available for the
+`account entity init` command.
+
+:::
+
 #### Register your Entity {#entity-register}
 
 In order for validators to become part of the validator set and/or the compute

examples/account/entity-init-o.y.in

@@ -0,0 +1 @@
+oasis account entity init -o entity.json

examples/account/entity-init.in.static

@@ -0,0 +1 @@
+oasis account entity init

examples/account/entity-init.out.static

@@ -0,0 +1,5 @@
+{
+  "id": "Bx6gOixnxy15tCs09ua5DcKyX9uo2Forb32O6Hyjoc8=",
+  "nodes": [],
+  "v": 2
+}