feat(UsageAlarmFactory): allow creating min/max count usage alarms without conflicting alarm names (#485)

The existing API results in conflicts due to the identical
`alarmNameSuffix`s.

This PR adds new replacement APIs to avoid changing existing alarm names
and better aligning the interface's prop naming.

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_By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license_

Author: Eugene Cheung