Support stable/EAP versions for gateway-plugin

[andreafalzetti]

Currently, Gateway-Plugin code, on main branch, supports only a single version: the stable. But there are moments when the plugin built with the Stable SKD stops working on EAP IDEs due to the incompatibility with the EAP SDK.

We solved this problem in our backend-plugin by always building two versions of the plugin: one for Stable IDEs using Stable SDK, and another for EAP IDEs using EAP SDK [#10595]. Now we need to apply a similar solution for the gateway-plugin.