Revert "Added school in Teacher constructor reference in TeacherResource"

This reverts commit 8517b82e0a4683cd4e0d593c9c4e116f054604bf.
Revert "Added REST endpoint for teacher-school connection, added school in teacher constructor"

This reverts commit 7f3f6ad0b1214b19d956d1e15b9bad56431a013c.
Revert "Made ManyToOne relation in Teacher.java to School.java"

This reverts commit a7e898b5d970d0aa02d057fe1ac72dfda5c227d4.