Some slash command args don't allow spaces

[tlmii]

Describe the bug

Some slash commands that take additional args simply split on space, so an arg (like a path) with a space in it will always fail to be parsed properly.

Affected version

No response

Steps to reproduce the behavior

1. Have a local copy of a marketplace in a folder that contains a space, e.g. "c:\my marketplace"
2. Run /plugin marketplace add c:\my marketplace\ and notice it fails
3. Run /plugin marketplace add "c:\my marketplace\" and notice it still fails

Expected behavior

Slash command args should be parsed in a quote-aware fashion or otherwise handle paths with spaces in them.

Additional context

Note that /cd and /context-dir add already handle paths with spaces