Build book appointments page

[SolviQorda]

• [x] Implement the input form
• [x] have it write to the db
• [x] build a basic appointment entry system
• [x] have a way of showing existing appointments, dependent on form input
• [x] have a way of choosing an existing appointment ( custom form )

[SolviQorda]

This is all done, but I'm experiencing bugs writing to the db, so the branch isn't merged yet.

[SolviQorda]

This is done now.