Add song import and export in Presenter and Planning

Right now there's no way to import or export individual songs in either Presenter or Planning. It would be great to be able to import songs from common file types — such as plain text (.txt), ProPresenter files, or other standard formats — instead of having to enter each song manually.
Export is just as limited. Planning currently only lets you export a song list, but there's no way to export the actual songs themselves. Being able to export individual songs (with lyrics and formatting) would let us back them up, store them separately, or reuse and process them for other tasks.
This matters to us because we use the songs in Plans as our main song database. Working with those lyrics for other purposes — printing for musicians, preparing materials, and so on — is really important, and it's essential that everyone works from one shared library so the lyrics are identical for the whole team.
Full import/export support for songs would make it much easier to move content in and out of the platform and keep our library portable and consistent.

In the beta version of Presenter, in the "About Presenter" window, there is the option to import songs from a number of formats (including ProPresenter files), which might be helpful.