Search function for Datasets

[EndallBatan93]

• [x] add the functionality to search through datasets, weather search for keys, values or everything

• [x] the Ui-element for the search should be placed in the datasets-visualizer component

[kKdH]

Maybe we should take a look at the query language used in Kibana. For example to searching for a field with a given value the syntax is: field:value

[reimarstier]

https://lucene.apache.org/core/3_6_0/queryparsersyntax.html