This replaces the `Then(string activityName)` method with `ThenNamed(string activityName)`.
A new method is added to allow connecting to activities by type name: `ThenTypeNamed(string activityTypeName)`.
The reason for this change and addition is to allow workflow builders to connect to activity types that do not have a corresponding type.
For example, the Telnyx project has an activity type provider that *dynamically* provides activity types based on Telnyx webhook callback types.
Temporal activities no longer have a generalised extension method
for registering them with a service collecton. It is still static and has
the same rough shape as an extension method. This way it is less
visible and less likely to be called by accident.
Also in-line with changes in this branch, things have been renamed
Timers → Temporal
The project/NuGet package for implementation logic relating to
temporal actions has been renamed:
Elsa.Activities.Timers.Hangfire → Elsa.Activities.Temporal.Hangfire
Elsa.Activities.Timers.Quartz → Elsa.Activities.Temporal.Quartz
Whilst large numbers of C# files are "changed" by this commit,
it's just a straight move to a new path.
