host.json schema validation — add OTel specific rules

#### What problem would the feature you're requesting solve? Please describe.
With OTel, users can sometimes configure host.json in a way that is incorrect, such as mixing OTel and App Insights settings.

#### Describe the solution you'd like
Update host.json schema on schemastore to flag incompatible configurations related to OTel, such as `telemetryMode=OpenTelemetry` but there's an `appInsights` section defined with sampling, etc.

#### Describe alternatives you've considered
Add warnings to the host, which we want to do as well.

@RohitRanjanMS

Start by locating the host.json schema on SchemaStore and review the telemetryMode and appInsights settings described in the issue. Define the incompatible OpenTelemetry and Application Insights combinations that should be flagged, then verify the schema reports those configurations while allowing valid ones.

Written by the indexing model from the issue text.