* renames `telemetry_key` to `microsoft_telemetry_key`
* renames `instrumentation_key` to `instance_telemetry_key`
* renames `can_share` to `can_share_with_microsoft`
* renames the `applicationinsights-rs` instances to `internal` and `microsoft` respective of the keys used during construction.
This clarifies the underlying use of Application Insights keys and uses struct tuple to ensure the keys are used correctly via rust's type checker.
