SLookup 4.1.0 - Add Graylog 4.1 Support

Add support for Graylog 4.1

Changes for StreamLookupFunction.java

1) Added required elasticsearch import for SortOrder
org.elasticsearch.search.sort.SortOrder;

2) Remove asElastic() as this method is no longer used

3) Switch timeRange builder to create which was changed when optional from/to fields were added in Graylog 4.1
   See https://github.com/Graylog2/graylog2-server/pull/9899/files

Changes for pom.xml

1) Added Elasticsearch 7.7 dependencies

2) Change Graylog version from 2.3.2 to 4.1.0

3) Removed graylog-plugin-pipeline-processor dependency

3) Change graylog-plugin-slookup-function to version 4.1.0 to indicate that it's for 4.1.x Graylog

Tested on Graylog 4.1.5
For version 4.0.5 to work revert the this.timeRange change on line 91 and switch Graylog versions in pom.xml