allow for easy reset of config files with a single command (#6041)

* allow for easy config reset with a single command

* add slightly better help, rebase

* add option to make no backups, make all backups unique through including UNIX Epoch Time in the filename

* time is now formatted in rfc3339

* time is now formatted in a window-friendly format

crates/nu-command/src/default_context.rs

@@ -343,6 +343,7 @@ pub fn create_default_context(cwd: impl AsRef<Path>) -> EngineState {
             WithEnv,
             ConfigNu,
             ConfigEnv,
+            ConfigReset,
             ConfigMeta,
         };