Single AppContext switch for the OpenTelemetry v11 behaviors

[ramonsmits]

Several OpenTelemetry behaviors become the only behavior in v11. There is no option to opt in or opt out in v11. Until v11, one AppContext switch enables all of them together:

AppContext.SetSwitch("NServiceBus.Core.OpenTelemetry.UseV11Behavior", true);

When the switch is on:

• Trace context and baggage use DistributedContextPropagator (W3C baggage format).
• Handler spans come from the NServiceBus.Core.Handler ActivitySource.
• An ambient transport SDK receive span becomes the parent of the incoming span. The sender span becomes a link.
• Span names include the destination or the message type, for example process orders, send Payment.
• The incoming span does not get the Start dispatching and Finished dispatching events.
• The metrics do not get the execution.result tag.
• Failures do not get the otel.status_code and otel.status_description tags and the exception.escaped attribute.

Removed:

• The switches UseDistributedContextPropagator, UseHandlerActivitySource and UseTransportActivityAsParent.
• The options UseMessageTypeNamesInSpanNames, EmitMessageDispatchingEvents and Meters.EmitExecutionResultTags. None of these shipped.

Not changed: PublishTraceMode. It keeps its option in v11.

File layout:

• obsoletes-v10.cs holds code that is obsolete in v10 and removed in v11. All v11 scaffolding now lives there, including V11BehaviorSwitch. OpenTelemetry/Tracing/obsolete_v11.cs is deleted.
• OpenTelemetry/Tracing/obsolete_v12.cs is renamed to obsoletes-v11.cs.
• The test projects get an obsoletes-v10.cs with the [OpenTelemetryV11Defaults] attribute. It runs a test with the switch on. Tests are named for the behavior; the attribute marks the mode.

Stacked on:

• Apply incoming trace state and baggage only with NServiceBus trace context #7954