Improve management of ALE when used as SiriusInterpreter

[dvojtise]

Description

This PR makes ALE interperter available all the time as a SiriusInterpreter (ie. a SiriusInterpreter is an interpreter used by Sirius in the odesign fields) (It was previously available only when running a single engine)

Expression in Sirius can now use ale: queries for both displaying runtime data while running a model AND displaying static information while editing a model (ie. as a replacement of [ /] or aql: queries)

This PR also fixes the display of ale: queries in Sirius 6.3.0 when no model is running (cf. #44)

This PR also provides a support for multiple model execution at the same time. (In the previous version, only one engine was available to provide runtime data to the SiriusIntepreter )

Changes

• the classes have been renamed in order to clearly show the relationship with SiriusInterpreter
• the ALESiriusInterpreterProvider is registered using the extension point in the plugin.xml
• ALESiriusInterpreter is now a singleton, engines register themselves as known engines. When evaluating a query, ALESiriusInterpreter either find the appropriate ALEEngine or creates a new one able to evaluate queries relative only to the static part of the model. A small cache avoid creating ALEEngine on every call.
• a new EngineAddon is used to dispose the resources when an engine is definitively closed
• the Launcher (launch configuration) implicitly registers the newly created engine to the known engines of ALESiriusInterpreter singleton. The launcher also implicitly adds the EngineAddon to the engine in order to unregister and free all the resources.

Contribution to issues

Closes #44
Contributes to gemoc/ale-lang#150

Companion Pull Requests

• Remove use of ALESiriusInterpreter in headles launcher gemoc-studio#216

[ebousse]

very nice!

Makes me think that a rather fun thing would be a generic SiriusInterpreter able to retrieve runtime data defined with any sort of metaprogramming approach.

[dvojtise]

Makes me think that a rather fun thing would be a generic SiriusInterpreter able to retrieve runtime data defined with any sort of metaprogramming approach.

This would be cool indeed because currently every engine provides its own way to access its RTD. Having a way to register "RTD Accessor service" in the GEMOC framework would probably help to design Sirius animation layers.