build: add issue template

[sicoyle]

The Dapr CPP SDK repo should have an issues template for when end users create issues when working with the project.

Describe the solution you'd like
We should abide by a standardized issue template across all SDK repositories.

To implement, we should add a ISSUE_TEMPLATE directory similar to that of:
https://github.com/dapr/java-sdk/tree/master/.github/ISSUE_TEMPLATE
https://github.com/dapr/python-sdk/tree/master/.github/ISSUE_TEMPLATE

Additional context
This will help to improve contributors to easily communicate their issues, as well as maintainers to easily understand what the issue at hand is.