Dev

This is mostly test-related fixes and improvement.

1. Re-importing a subscription when initializing each test to avoid subscription interference.

2. Fix SAS Uri tests.
 - Removing subscriptions before uploading with SAS URI.
 - Re-Importing a subscription after uploading.
 - Use https instead of http
 - Create a storage container for SAS Uri testing.

3. Update AzureVM test for more coverage of Hi-MEM test

4. Remove certificate files and Create a certificate during test.

5. Fix RemoveAzureSubscriptions method

6. Fix the method for getting a default location