Allow setting skiko properties using skiko.properties file inside jar (#994)

In order to use two different versions of skiko in one app (using
multiple classloaders), it is required to use the unpacking strategy, as
the skiko.library.path is a system property, which is same for all
classloaders.

This change will allow to use presigned natives shipped together with
the app, while still being able to use multiple versions as the property
skiko.library.path will be loaded from current classloader resources,
with fallback to system property.
Co-authored-by: Jakub Senohrabek <jakub@senohrabek.net>

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/SkikoProperties.kt

 package org.jetbrains.skiko
 
-import java.lang.System.getProperty
+import java.util.*
 
 // TODO maybe we can get rid of global properties, and pass SkiaLayerProperties to Window -> ComposeWindow -> SkiaLayer
 @Suppress("SameParameterValue")
@@ -89,6 +89,19 @@ object SkikoProperties {
 
     val macOsOpenGLEnabled: Boolean get() = getProperty("skiko.macos.opengl.enabled")?.toBoolean() ?: false
 
+    private val properties = run {
+        val resourcePropertiesEnabled = System.getProperty("skiko.resource.properties.enabled")?.toBoolean() ?: false
+        val resources = if (resourcePropertiesEnabled) {
+            SkikoProperties::class.java.classLoader.getResourceAsStream("skiko.properties")
+        } else {
+            null
+        }
+        val systemProps = System.getProperties()
+        if (resources == null) systemProps else Properties(systemProps).apply { load(resources) }
+    }
+
+    private fun getProperty(key: String): String? = properties.getProperty(key)
+
     internal fun parseRenderApi(text: String?): GraphicsApi {
         when(text) {
             "SOFTWARE_COMPAT" -> return GraphicsApi.SOFTWARE_COMPAT