Support date var template(moment.js) in folder path & image name

[Harrd]

Support Date Template Variables in Path by Changing getAttachmentFolderPath/getPastedImageFileName Behavior

For example: /dir1/${date:YYYY}/${date:MM}/${filename} will be transformed to /dir1/2024/03/target_file/

Implementation Details:

• Use a regex pattern to match date variables (vars starting with ${date:} / ${filename}).

File Attachment Folder Behavior:

• If the file already has an attachment folder: Use the earliest folder that matches the regex.
• If the file has no attachment folder (no folder matches the regex): Create a new one using the current date and time.

Important Notes:

• getAttachmentFolderPath will become asynchronous, so adjust the invocation timing in the handlePaste event accordingly.
• Only support fixed digit formats in ${date:} like YYYY, MM, DD, Q. (${date:YYYY} will compile to d[4] regex for matching earliest attachment folder)

conf example: