Update version of Bootstrap per CVE-2018-14041

Issues 252,253: Browse by title and browse by metadata (author)

Conflicts:
	src/app/core/shared/operators.ts

Resolvers for item, collection and community home page

Merge branch 'browse-by-features' of https://github.com/atmire/dspace-angular into browse-by-features

Conflicts:
	src/app/core/data/data.service.spec.ts

Conflicts:
	src/app/core/core.module.ts
	src/app/core/shared/operators.ts
	src/app/shared/object-grid/item-grid-element/item-grid-element.component.html
	src/app/shared/object-list/item-list-element/item-list-element.component.html
	src/app/shared/shared.module.ts

Search features

Conflicts:
	src/app/core/shared/operators.ts

This reverts commit d9e70bd4.

Conflicts:
	src/app/shared/object-grid/item-grid-element/item-grid-element.component.html
	src/app/shared/object-list/item-list-element/item-list-element.component.html