added l0 and linf for count

[chinmayshah99]

Description

Fixes #276 Added l0 and linf as arguments that can be taken underneath Count().

How has this been tested?

• added more tests

Checklist

• [ ] I have followed the Contribution Guidelines and Code of Conduct
• [ ] I have commented my code following the OpenMined Styleguide
• [ ] I have labeled this PR with the relevant Type labels
• [x] My changes are covered by tests