Encode filepaths to be safe on Windows

This changes the file paths to use characters that are safe for Windows.

Channges the output of the following:
* Package cache directory
* Generated pkl-doc files
* Kotlin generated code

Unsafe characters are encoded as (<hex>).
For example, the colon character `:` is encoded as `(3a)`.

Additionally, this changes the cache directory prefix (package-1 to
package-2).

Follows the design of https://github.com/apple/pkl-evolution/pull/3

pkl-codegen-kotlin/src/main/kotlin/org/pkl/codegen/kotlin/KotlinCodeGenerator.kt

@@ -22,6 +22,7 @@ import java.net.URI
 import java.util.*
 import org.pkl.core.*
 import org.pkl.core.util.CodeGeneratorUtils
+import org.pkl.core.util.IoUtils
 
 data class KotlinCodegenOptions(
   /** The characters to use for indenting generated Kotlin code. */
@@ -89,7 +90,7 @@ class KotlinCodeGenerator(
 
   private val propertyFileName: String
     get() =
-      "resources/META-INF/org/pkl/config/java/mapper/classes/${moduleSchema.moduleName}.properties"
+      "resources/META-INF/org/pkl/config/java/mapper/classes/${IoUtils.encodePath(moduleSchema.moduleName)}.properties"
 
   private val propertiesFile: String
     get() {
@@ -195,7 +196,7 @@ class KotlinCodeGenerator(
     }
 
   private fun relativeOutputPathFor(moduleName: String): String {
-    val nameParts = moduleName.split(".")
+    val nameParts = moduleName.split(".").map(IoUtils::encodePath)
     val dirPath = nameParts.dropLast(1).joinToString("/")
     val fileName = nameParts.last().replaceFirstChar { it.titlecaseChar() }
     return if (dirPath.isEmpty()) {

pkl-codegen-kotlin/src/test/kotlin/org/pkl/codegen/kotlin/KotlinCodeGeneratorTest.kt

@@ -1501,6 +1501,24 @@ class KotlinCodeGeneratorTest {
     confirmSerDe(bigStruct)
   }
 
+  @Test
+  fun `encoded file paths`(@TempDir path: Path) {
+    val kotlinCode =
+      generateKotlinFiles(
+        path,
+        PklModule(
+          "FooBar.pkl",
+          """
+      module `Foo*Bar`
+      
+      someProp: String
+    """
+            .trimIndent()
+        )
+      )
+    assertThat(kotlinCode).containsKey("kotlin/Foo(2a)Bar.kt")
+  }
+
   private fun generateFiles(tempDir: Path, vararg pklModules: PklModule): Map<String, String> {
     val pklFiles = pklModules.map { it.writeToDisk(tempDir.resolve("pkl/${it.name}.pkl")) }
     val evaluator = Evaluator.preconfigured()