Send multiple attachments at a time

[tomastiminskas]

Implement the logic to allow sending multiple attachments together (up to 10) and add ability to select up to 10 files from Finder window when tapping on File option on the new + button menu

Base branch: tt/feature/attachments-preview

General requirements

• All designs have been built already on tt/feature/attachments-preview branch. So they should be used
• Implement the logic to allow sending multiple attachments together
• Implement new + button menu logic with ability to select files from Finder

Specific requirements

• Build the logic based on existing attachments logic but extending it to allow multiple attachments sending

Acceptance Criteria

• Apply logic and test deeply into all scenarios
• Record a video with loom for review when task is completed

Logic references

1. NewChatViewModel - func insertProvisionalAttachmentMessageAndUpload: Right now we are creating a provisional message (message record in device db with a provisional id - negative id), then starting the file upload, and finally sending it when upload completed.
2. AttachmentsManager: func uploadData: in the progress callback of the uploadData method in AttachmentsManager, we are updating the upload progress state of the DataSource item so the row is automatically updated using delegate?.didUpdateUploadProgress and the provisionalMessage?.id

All this logic needs to adapted to allow multiple sendings at a time. Actually the logic needs to be implemented this:

1. Create the provisional messages for all sending attachments (this will create and show the rows in the chat view)
2. Start uploading and sending files one at a time so when first completes, then second starts to upload and send

[Khaalid-oh]

I can help with this