Expandable search form in header with tests (& e2e tests)

Squashed:
66021: Expandable search form in header
66021: Adjustment small screens
66021: search icon now pressable and css partially moved to bootstrap classes
66021: start testing of header search box; TODO fix e2e
66021: E2E Tests
66021: Header search box now with angular animation and bootstrap > css; e2e fix
66021: feedback 2019-12-19 style changes
66021: Fix navbar search tests
Patch: add opacity to header search animation  Change the input style
66021: expandable search navbar - tests
66021: Expandable search form in header
Small fix after rebasing upstream/master