clean teachers

app/controllers/admin/education/programs_controller.rb

app/controllers/admin/education/teachers_controller.rb

app/models/education/program.rb

app/models/education/program/teacher.rb

app/models/university/person.rb

app/views/admin/education/programs/_form.html.erb

app/views/admin/education/programs/show.html.erb

app/views/admin/education/teachers/_form.html.erb

app/views/admin/education/teachers/edit.html.erb

...grate/20220105151548_create_education_program_teachers.rb

...05151606_remove_education_programs_teachers_join_table.rb

db/schema.rb

test/fixtures/education/program/teachers.yml

test/models/education/program/teacher_test.rb