Improve Kover setup by using only convention plugins (#6213)

* Improve Kover setup using convention plugins.
* Add a new JVM library convention plugin with Kover support

plugins/src/main/kotlin/io.element.android-library.gradle.kts

@@ -11,6 +11,7 @@
  */
 import extension.androidConfig
 import extension.commonDependencies
+import extension.setupKover
 import org.gradle.accessors.dm.LibrariesForLibs
 
 val libs = the<LibrariesForLibs>()
@@ -33,6 +34,8 @@ kotlin {
     }
 }
 
+setupKover()
+
 dependencies {
     commonDependencies(libs)
     coreLibraryDesugaring(libs.android.desugar)