Subtask 3: Change APIs to support new fields

Story Points: 3

# How?

3. Change APIs to point to do basic CRUD operations. (Don't be worried about router implementation)
- `amplify/ts-code/src/db/MainTable.ts`
- Add new fields to `create` function.
- `amplify/ts-code/src/db/ItemTable.ts`
- Add new fields to `create` function.
- Change `key` input in `update` function to only allow `notes` to be changed.
- Add `returnTime` to be a expected input to `changeBorrower`
- Fill `borrowTime` and `returnTime` fields on borrow
- Empty `borrowTime` and `returnTime` fields on return
- `amplify/ts-code/src/db/BatchTable.ts`
- Change to point to main table instead of item table
- Only works because batch table is empty right now.
- `amplify/ts-code/src/api/AddItem.ts` to recieve and add to new fields

More details in https://github.com/a2n-seattle/rms-app/issues/244