Bugfix/cache sync - Githubissues

This PR fixes the bugs that user @software312 reported:

Before login
- Archive not working
- Latest bill on analytics screen is shown as 1970 after creating a bill before today.
After login
- User can see duplicates of their previous data before login.

Fixes done

Archive not working
- The main problem with cache sync-ing comes from the check of bill.id & bill.tempID in the bills to be archived.
- Added a check for bill.id is null first comparing to cache's bills.
Latest bill on analytics screen is shown as 1970 after creating a bill before today
- This happens because of the default dayjs() object.
- Add checks for empty bills, and improve placeholder texts.
User can see duplicates of their previous data before login.
- It was observed that login was very laggy, as a result user can click the signup/login button many times. Hence multiple sync-ing was happening.
- Quick fix is to add disabled & loading state to button once it is clicked.
Also added disabled and loading state to add bill form, and improved bill reminder form ui.