LPS-47341 Fix snippet processing in OpenSearch. Also, avoid processing "null" summaries returned by some indexers
LPS-47341 Certain indexers may set "content" or "title" to null which can lead to NPE
LPS-47341 Date fields should be set to "stored" explicitely, since the default is "false" which causes that e.g. field "modified" is missing from result Document hit and it leads to a ParseException in OpenSearch
LPS-47341 src format
SourceFormatter - Remove legacy code. It does not work properly for plugins and is no longer needed since 00c1a3c8a8765a4c071874e3f1b4fde0857fb4c7
LPS-49944 Change styling to make it clear distinction between different sections