[Improvement] Add multiple notes feature to the following modules:
- Supplier
- Product
- Purchase
- Customer
- Vehicle
- Jobcard
- Quotation
- Invoice
[Improvement] Display the total amount for all invoices within a selected date range in the report module.
[Improvement] Design an email template for sent mails.
[Improvement] Add some default observation libraries.
[Bug] Fix tax issue in the view invoice module.
