feat(T2M): Display all semesters on webpage

...tml/src/tdt4250/spp/html/main/studyplan2TextGenerator.mtl

tdt4250.spp.html/src/tdt4250/spp/html/source/SampleSpp.xmi

tdt4250.spp.html/src/tdt4250/spp/html/target/NTNU.html

tdt4250.spp.model.edit/plugin.properties

...l.edit/src/tdt4250/spp/provider/SemesterItemProvider.java

tdt4250.spp.model/model/spp.genmodel

tdt4250.spp.model/src/tdt4250/spp/Semester.java

tdt4250.spp.model/src/tdt4250/spp/SppPackage.java

...p.model/src/tdt4250/spp/examples/LoadResourceExample.java

tdt4250.spp.model/src/tdt4250/spp/impl/SemesterImpl.java

tdt4250.spp.model/src/tdt4250/spp/impl/SppPackageImpl.java