Due to a bug with registering AutoMapper profiles, only the first mapping profile would get registered.
Also merged AutoMapper utilities into Elsa.Core.
* Added MySqlContext
* Added MySqlContextFactory
* Added Pomelo.EntityFrameworkCore.MySql nuget package
* Added initial MySqlContext migrations
* Added support for creating derived ElsaContexts:
- Added new protected constructor based on following post
- https://github.com/dotnet/efcore/issues/7533
* Added Sample 24 - MySql provider with migration execution
* Updated other samples that needed to define the derived ElsaContext
* Added summary to ElsaContext constructor
* Updated persistence/Elsa.Persistence.EntityFrameworkCore MD file with MySql example
* Added PostgreSql support to Elsa.Persistence.EntityFrameworkCore via Npgsql.
* Customize Elsa.Persistence.EntityFrameworkCore Migrations and Schema.
* Added Context factory in Sample23 to use the IDbContextCustomSchema.
* Refactor the Custom Schema support to use the EFCore IDbContextOptionsExtension.
* Variables are now stored including their type name for automatic deserialization into their actual type. This is important for use in expressions.
* **SplitObject** and **ExecuteMethod** now use workflow expressions instead of variable names. This allows for more flexibility.
* Improved **Join** activity to allow proper function within looping constructs.
* Improved Variables performance. Variables are no longer serialized/deserialized upon writing/reading perspectively, only when the workflow instance is persisted.
* Fix many things. Few more samples left to fix
* Fix all the samples
* Introduce service configurator
* Implement cache signaling and refreshing workflow registry
* Add Sample16 demonstrating dashboard + workflow host combined
* Bugfix where non-published versions of worklows are triggered
