Create new route to display IVC appointments

[vcheeze]

Expected Result: being able to view booked appointment timeslots on a new route, i.e. www.gopherwoodclinic.org/appointments. Features may include being able to sort, filter, and search data.

Steps:

• Create new .svelte file under the routes/ folder. Refer to the other .svelte files to get started. Use the basic HTML table element for now.
• Create new route under routes/api/ folder that retrieves all appointments (refer to routes/api/getBookedSlots.js, which gets timeslots for a given date).
• Implement simple login system to ensure only clinic staff are able to view this page (will probably be done by @vcheeze )
• [optional]: once the above is done, consider simply modifying routes/api/getBookedSlots.js in order to query timeslots dynamically, i.e. for a certain date, for a range of dates, for a certain patient, etc.)
• [optional]: see how we can start creating a table component of our own that can display the data as well as support the more advanced functionality that will come later, i.e. sorting, filtering, searching, etc.

[vcheeze]

Some feedback on the 1st iteration:

• Use svelte-calendar for the dates field
• Make table headers internationalized (name, date, and time should display in Chinese and English depending on the selected language)
• Populate initial table with all future appointments
• Add spinner - show it when user presses the submit button, and hide it when the data is retrieved
• Show a 'no data found' message when user's filter returns no data