dolt_clone and --user

[macneale4]

Previously the dolt_clone() stored procedure would take the --user flag, but not use it in a gRPC call to a sql-server. This
addresses this limitation, and adds a test to verify it works.

[coffeegoddd]

@macneale4 DOLT

comparing_percentages
99.998787 to 99.998787

version	result	total
1634556	not ok	72
1634556	ok	5937385

version	total_tests
1634556	5937457

correctness_percentage
99.998787

[coffeegoddd]

@coffeegoddd DOLT

comparing_percentages
99.998787 to 99.998787

version	result	total
9aae715	not ok	72
9aae715	ok	5937385

version	total_tests
9aae715	5937457

correctness_percentage
99.998787

[reltuk]

LGTM!

[coffeegoddd]

@macneale4 DOLT

comparing_percentages
99.998787 to 99.998787

version	result	total
52a32ff	not ok	72
52a32ff	ok	5937385

version	total_tests
52a32ff	5937457

correctness_percentage
99.998787