Implement note asset handling for SQLite note store
When assets (i.e. images or other attachments) are added to a note, the assets should be saved in such a way that they can be accessed/displayed via the Markdown. For this solution, we will create a directory that lives in the same directory the user specifies for the .db file. The attachment data will then be saved to this directory and the Markdown link will point to this new location. This will allow for the user to be able to easily save screenshots and such to notes without worrying about where the attachment data is saved.