Resolve "Rework Tests"

Closes #31

See merge request !25

added start files

See merge request !24

delete function

See merge request !23

Resolve "Frontend: Navbar mit 3 Reitern hinzufügen"

Closes #21

See merge request !21

Resolve "Backend: put("/project") Parameter-Liste statt Project Object"

Closes #23

See merge request !18

Resolve "HTTP codes"

Closes #29

See merge request !19

Resolve "Backend: speichern vom Bearbeiten"

Closes #19

See merge request !16

Resolve "Datumsformart im Model prüfen"

Closes #28

See merge request !14

Resolve "Backend: Mehre Projekte mit selber Id"

Closes #26

See merge request !15

Resolve "Tests"

Closes #25

See merge request !13

Resolve "Frontend: projekt hinzufügen post request"

Closes #22

See merge request !11

Resolve "Erweitern der README"

Closes #12

See merge request !10

Resolve "Frontend Zeit planug"

Closes #15

See merge request !8

Resolve "Backend: Startzeit + Dauer hinzufügen"

Closes #20

See merge request !7

This reverts commit a6b0c87b.

This reverts commit 2f9a8c4a.

This reverts commit 99c15e44.

This reverts commit ef811d23.

This reverts commit 33c50d98.