Refactor

Remove dead code, warnings and copypaste.
OVT-7532 Remove some hibernate caching

Which seemingly caused these problems
Deleted vaadin implementation from koodisto
KH-190: Add unique filter for codes

Helps to prevent duplicates from showing. Though better way is probably
not to return duplicates at all through json...
OVT-7280: Delete relation between codes

Had to remove KoodistonSuhde from KoodistoVersio's ylakoodistot and
alakoodistot sets first before removing. Which is more than a little
perplexing.
Fix test
OVT-7280: Prevent deletion of codes relations

If there is a code element relation between code elements in codes, then
deleting codes relation is prevented.
OVT-7280: Check for presentable instead of null

Fix for the derp....
KH-193: Prevent creating more than one relation

Between codes which naturally prevents creationg of multiple code
element relations too.
Unit tests for errors related to relations
Merge branch 'develop'

Conflicts:
	koodisto-app/pom.xml (resolved by removing)
Merge branch 'master' into prod

Conflicts (resolved by removing files):
	koodisto-app/pom.xml
	koodisto-app/src/main/webapp/WEB-INF/web.xml