Add custom export plugin mechanism. ENG-4518
Add test for export custom config.
Test for export cant be done without a catalog with export tables.
Fixes
Merge branch 'master' of github.com:VoltDB/voltdb into ENG-4518
rename as connector
ENG-4518 refactor/rename ExportClient*
fix licensecheck
Update getDeploymentCRC for new attributes.
Rename back to keep existing clients out there happy.
Add generic property in custom export test.
Merge branch 'master' into ENG-4518
combine in CrC generation.
Organize imports.
Complete sentences.
Wrap long lines.
realign
Merge branch 'master' into ENG-4518
add test for custom catalog values check.
Add custom export client sample no op class for testing with classloading.
no actual export is done.