Seasonal Stage Lists and More

Adds support for official stage lists to the launcher.

These stage lists can be found in hdr-stages, and will not overwrite your own personal stage list.

Also fixes some oversights on Linux.

What's Changed

• Make sure config files only live in one place on Linux by @BrianAllred in #78
• add seasonal stagelist capability by @SuddyN in #81

New Contributors

• @BrianAllred made their first contribution in #78

Full Changelog: v0.6.2...v0.7.0