Reservation re - design

[StanislawHornaGitHub]

• add service tables and constraints

• add service_view

• add update and insert functions

• add triggers

• add privileges for api users to service_view

• unify naming

• update docs

• fix typos, add to table of contents

• remove api read user

• add function to check if room is available

• add room id to thrown exception

• change func name is_room_available -> check_room_availability

• fix tests related to dates to reflect new verification