Gh 2723 refactor to open cypher csv

[p3430233]

Refactored the csv export functionality. A user can now pass a csv format which is then used to build its respective generator. This makes use of the existing ToCsv operation and handler rather than building a new op and handler for each format

[codecov-commenter]

Codecov Report

:exclamation: No coverage uploaded for pull request base (v2-alpha@2c1ac34). Click here to learn what that means. The diff coverage is n/a.

@@             Coverage Diff             @@
##             v2-alpha    #2751   +/-   ##
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  Coverage            ?   65.74%           
  Complexity          ?     2462           
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  Files               ?      869           
  Lines               ?    27399           
  Branches            ?     3138           
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  Hits                ?    18013           
  Misses              ?     8032           
  Partials            ?     1354           

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[GCHQDeveloper314]

The file rest-api/core-rest/src/test/java/uk/gov/gchq/gaffer/rest/service/v2/OperationServiceV2IT.java is showing as only copyright changed. I think this can be undone as well, such that the file is not mentioned in the changes at all, it should never have been there.