The launcher code was in a position ripe for sphagetti, so this rewrites it in a more robust way.
In addition to cleaner code, this provides the following changes:
- Removal of obsolete Mojang authentication
- The rebasing of some internal state into a Sled database
- Tweaks which make some internal mechanisms more robust (e.g. profiles which fail to load can be removed)
- Additional tooling integration such as direnv
- Distinct public API to avoid messing with too much internal code
- Unified error handling in the form of `theseus::Error` and `theseus::Result`
* 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
