Add module service injection mechanism

- Introduced `ModuleService` annotation for marking injectable services.
- Added `ModuleHolder` class to hold injected module services.
- Implemented `ModuleServiceInjector` to dynamically inject beans annotated with `ModuleService` into `ModuleHolder`.

Author: tuplle

application-engine/.gitignore

@@ -143,3 +143,5 @@ log/
 /src/main/resources/certificates/private.der
 /src/main/resources/certificates/public.crt
 /modules/
+!src/main/java/**/modules
+!src/main/groovy/**/modules

application-engine/src/main/groovy/com/netgrif/application/engine/integration/modules/ModuleHolder.groovy

@@ -0,0 +1,7 @@
+package com.netgrif.application.engine.integration.modules
+
+/**
+ * A class where the module services are injected. The plugins are injected into metaclasses
+ * */
+class ModuleHolder {
+}

application-engine/src/main/groovy/com/netgrif/application/engine/integration/modules/ModuleServiceInjector.groovy

@@ -0,0 +1,30 @@
+package com.netgrif.application.engine.integration.modules
+
+import com.netgrif.application.engine.configuration.ApplicationContextProvider
+import com.netgrif.application.engine.startup.ApplicationEngineFinishRunner
+import com.netgrif.application.engine.startup.annotation.RunnerOrder
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+import org.springframework.boot.ApplicationArguments
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty
+import org.springframework.stereotype.Component
+
+@Component
+@RunnerOrder(209)
+@ConditionalOnProperty(value = "nae.modules.services.enabled", havingValue = "true", matchIfMissing = true)
+class ModuleServiceInjector implements ApplicationEngineFinishRunner {
+
+    private static final Logger log = LoggerFactory.getLogger(ModuleServiceInjector.class)
+
+    @Override
+    void run(ApplicationArguments args) throws Exception {
+        def injectableBeans = ApplicationContextProvider.getAppContext().getBeansWithAnnotation(ModuleService.class)
+        if (!injectableBeans.isEmpty()) {
+            MetaClass holderMetaClass = ModuleHolder.metaClass
+            injectableBeans.forEach((key, value) -> {
+                log.debug("Injecting module service {} into action delegate make it available under module.{}", key, key)
+                holderMetaClass[key] = value
+            })
+        }
+    }
+}

application-engine/src/main/groovy/com/netgrif/application/engine/petrinet/domain/dataset/logic/action/ActionDelegate.groovy

@@ -2,6 +2,7 @@ package com.netgrif.application.engine.petrinet.domain.dataset.logic.action
 
 import com.netgrif.application.engine.auth.service.GroupService
 import com.netgrif.application.engine.auth.service.UserService
+import com.netgrif.application.engine.integration.modules.ModuleHolder
 import com.netgrif.application.engine.petrinet.service.interfaces.IPetriNetService
 import com.netgrif.application.engine.adapter.spring.petrinet.service.ProcessRoleService
 import com.netgrif.application.engine.adapter.spring.workflow.domain.QCase
@@ -200,6 +201,8 @@ class ActionDelegate {
 
     PluginHolder Plugin
 
+    ModuleHolder Module
+
     /**
      * Reference of case and task in which current action is taking place.
      */
@@ -222,6 +225,7 @@ class ActionDelegate {
         this.outcomes = new ArrayList<>()
         this.Frontend = new FrontendActionOutcome(this.useCase, this.task, this.outcomes)
         this.Plugin = new PluginHolder()
+        this.Module = new ModuleHolder()
     }
 
     def initFieldsMap(Map<String, String> fieldIds) {

application-engine/src/main/java/com/netgrif/application/engine/integration/modules/ModuleService.java

@@ -0,0 +1,9 @@
+package com.netgrif.application.engine.integration.modules;
+
+import java.lang.annotation.*;
+
+@Documented
+@Target({ElementType.TYPE})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface ModuleService {
+}