feat: add "Full Name" field to user creation (#13659)

Adds the ability to specify "Full Name" (a.k.a. Name) when
creating users either via CLI or UI.

cli/testdata/coder_login_--help.golden

@@ -10,6 +10,9 @@ OPTIONS:
           Specifies an email address to use if creating the first user for the
           deployment.
 
+      --first-user-full-name string, $CODER_FIRST_USER_FULL_NAME
+          Specifies a human-readable name for the first user of the deployment.
+
       --first-user-password string, $CODER_FIRST_USER_PASSWORD
           Specifies a password to use if creating the first user for the
           deployment.

cli/testdata/coder_users_create_--help.golden

@@ -7,6 +7,9 @@ OPTIONS:
   -e, --email string
           Specifies an email address for the new user.
 
+  -n, --full-name string
+          Specifies an optional human-readable name for the new user.
+
       --login-type string
           Optionally specify the login type for the user. Valid values are:
           password, none, github, oidc. Using 'none' prevents the user from

cli/testdata/coder_users_list_--output_json.golden

@@ -3,7 +3,7 @@
     "id": "[first user ID]",
     "username": "testuser",
     "avatar_url": "",
-    "name": "",
+    "name": "Test User",
     "email": "testuser@coder.com",
     "created_at": "[timestamp]",
     "last_seen_at": "[timestamp]",