(build) Add templated notifications to all build configurations

Description Of Changes

This PR makes each build configuration in the TeamCity KTS file reference a template containing standard Slack notification configuration, which applies said configuration to the build configuration without having to duplicate it in each.

Motivation and Context

Enables standard notification configuration across all build configurations in this project.

Testing

This has been tested by pointing a development TeamCity instance at the branch from which this merge request is originating.

Operating Systems Testing

N/A

Change Types Made

Build configuration change (non-breaking)

* [ ] Bug fix (non-breaking change). * [ ] Feature / Enhancement (non-breaking change). * [ ] Breaking change (fix or feature that could cause existing functionality to change). * [ ] Documentation changes. * [ ] PowerShell code changes.

Change Checklist

[ ] Requires a change to the documentation.
[ ] Documentation has been updated.
[ ] Tests to cover my changes, have been added.
[ ] All new and existing tests passed?
[ ] PowerShell code changes: PowerShell v2 compatibility checked?

Related Issue

N/A

chocolatey / choco