work on overview thumbnail image
Prefer large image
Rework the default search UI. Add some info on the home page (latest, most popular, browse topics). Make the search results display properly.
Add a fix when filters are applied to text substitution.
Merge branch 'refactor_search' of https://github.com/geonetwork/core-geonetwork into refactor_search
Commit every 500 records indexed so that large number of metadata can be bulk indexed without OOM exceptions.
remove extra line in template rendering
when click on viewer image open floating image
Don't show small thumbnails if large exists
overview thumbnail larger and centered
some fixes for database migration
Merge branch 'refactor_search' of github.com:geonetwork/core-geonetwork into geocat_searchui_develop

Conflicts:
	bin/start.ps1
	core/src/main/java/org/fao/geonet/kernel/IndexMetadataTask.java
	web-ui/src/main/resources/catalog/locales/en-search.json