Add EventCounterCollectionModule

[cijothomas]

Fix Issue #1222 .

WIP:

1. No tests added, but validated with real 3.0-preview6 apps.
2. This is intended to be released as a separate Nuget package. Submitting this PR to get early feedback about implementation.

• [ ] I ran Unit Tests locally.

For significant contributions please make sure you have completed the following items:

• [ ] Changes in public surface reviewed

• [ ] Design discussion issue #

• [ ] CHANGELOG.md updated with one line description of the fix, and a link to the original issue.

• [ ] The PR will trigger build, unit tests, and functional tests automatically. If your PR was submitted from fork - mention one of committers to initiate the build for you. If you want to to re-run the build/tests, the easiest way is to simply Close and Re-Open this same PR. (Just click 'close pull request' followed by 'open pull request' buttons at the bottom of the PR)

• Please follow [these] (https://github.com/Microsoft/ApplicationInsights-dotnet-server/blob/develop/CONTRIBUTING.md) instructions to build and test locally.

[cijothomas]

closing in favor of https://github.com/microsoft/ApplicationInsights-dotnet-server/pull/1224/files