feat(config): simplify list command and add subcommand aliases

- config list: remove -l/--long option, always display URL
- config list: add ls alias (already existed, kept)
- config delete: add rm alias (alongside existing remove alias)
- README: add config update, config list, config delete sections

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

README.md

@@ -18,6 +18,32 @@ Create remote host configuration
 mdrs config create neurodata https://neurodata.riken.jp/api
 ```
 
+### config update
+
+Update the URL of a registered remote host.
+
+```shell
+mdrs config update neurodata https://neurodata.riken.jp/api
+```
+
+### config list
+
+List registered remote hosts.
+
+```shell
+mdrs config list
+mdrs config ls
+```
+
+### config delete
+
+Remove a registered remote host.
+
+```shell
+mdrs config delete neurodata
+mdrs config rm neurodata
+```
+
 ### login
 
 Login to remote host