Initial draft of profile metadata format & CLI (#17)

* Initial draft of profile metadata format

* Remove records, add Clippy to Nix, fix Clippy error

* Work on profile definition

* BREAKING: Make global settings consistent with profile settings

* Add builder methods & format

* Integrate launching with profiles

* Add profile loading

* Launching via profile, API tweaks, and yak shaving

* Incremental update, committing everything due to personal system maintainance

* Prepare for review cycle

* Remove reminents of experimental work

* CLI: allow people to override the non-empty directory check

* Fix mistake in previous commit

* Handle trailing whitespace and newlines in prompts

* Revamp prompt to use dialoguer and support defaults

* Make requested changes

.gitignore

@@ -3,3 +3,9 @@ node_modules/
 .svelte-kit/
 theseus_gui/build/
 WixTools
+
+[#]*[#]
+
+# TEMPORARY: ignore my test instance and metadata
+theseus_cli/launcher
+theseus_cli/foo