Remember previous folder for file picker

[daniel-lerch]

Currently, when manually opening a file in noScribeEdit, the file picker defaults to the program's installation folder. This is inconvenient, as users typically do not store files in this location.

Intended Behavior:

• The file picker should default to the user's profile directory (e.g., ~/Documents or equivalent) when opened for the first time.
• After the first use, it should remember and default to the last directory from which a file was opened.

[kaixxx]

Good idea, I'll put this on my list...