Search improvements

[patrick-austin]

Add support for new Lucene based free text search functionality:

• new searchInvestigations accepting additional parameters such as facets and sorting
• new searchInvestigations accepting additional parameters such as facets and sorting
• new searchInvestigations accepting additional parameters such as facets and sorting
• changes to existing lucenePopulate so that the client call and resultant behaviour is unchanged, but it gives the parameters that icat.server now expects

Note that existing methods for searching are unchanged (these have less features and only return ids rather than full documents).

[VKTB]

This looks good to me.

I did notice code duplication in the searchInvestigations, searchDatasets and searchDatafiles methods in the ICAT class which could probably be avoided by refactoring the common logic into a new method that these methods can call.

[patrick-austin]

I did notice code duplication in the searchInvestigations, searchDatasets and searchDatafiles methods in the ICAT class which could probably be avoided by refactoring the common logic into a new method that these methods can call.

Yeah you're right, a lot of the JSON building could be refactored. I might leave the old searchInvestigations, searchDatasets and searchDatafiles functions (those that are called by the Topcat-style endpoint) unchanged, since we'd delete them in a future version anyway, but there's no reason to duplicate code like they did in our new functions.

[VKTB]

This looks much nicer now, thank you for making the changes @patrick-austin. I forgot to say initially but, yes, the deprecated methods do not need to be updated.