CMS-1655 Content Manager: Replace DeleteContentWindow with a new DeleteContentDialog

Implement DeleteContentDialog that extends DeleteDialog and replace DeleteContentWindow with it.
Merge branch 'master' of github.com:enonic/wem-ce into CMS-1655

Conflicts:
	modules/wem-webapp/src/main/webapp/admin2/api/js/api.d.ts
	modules/wem-webapp/src/main/webapp/admin2/api/js/api.js
	modules/wem-webapp/src/main/webapp/admin2/api/js/api.js.map
	modules/wem-webapp/src/main/webapp/admin2/apps/content-manager/js/all.js
	modules/wem-webapp/src/main/webapp/admin2/apps/content-manager/js/all.js.map
Merge pull request #237 from enonic/CMS-1655

CMS-1655 Content Manager: Replace DeleteContentWindow with a new DeleteC...