The expirationDate for new shares needs to be in the future. Using
static dates in the tests means we need to update them every now an
then. This adjusts the helpers to allow relative date formats like
"+3 days" and "tomorrow" when creating shares.
* divide shareNg test suite into 2 parts
* update directory name in expected failure file
* separate apisharingNg suite
* separate shareNg test suite to 3 parts
* remove unused context files from test suites