Add support for Windows (#492)

This adds support for Windows.
The in-language path separator is still `/`, to ensure Pkl programs are cross-platform.

Log lines are written using CRLF endings on Windows.
Modules that are combined with `--module-output-separator` uses LF endings to ensure
consistent rendering across platforms.

`jpkl` does not work on Windows as a direct executable.
However, it can work with `java -jar jpkl`.

Additional details:

* Adjust git settings for Windows
* Add native executable for pkl cli
* Add jdk17 windows Gradle check in CI
* Adjust CI test reports to be staged within Gradle rather than by shell script.
* Fix: encode more characters that are not safe Windows paths
* Skip running tests involving symbolic links on Windows (these require administrator privileges to run).
* Introduce custom implementation of `IoUtils.relativize`
* Allow Gradle to initialize ExecutableJar `Property` values
* Add Gradle flag to enable remote JVM debugging

Co-authored-by: Philip K.F. Hölzenspies <holzensp@gmail.com>

buildSrc/src/main/kotlin/pklAllProjects.gradle.kts

@@ -93,3 +93,28 @@ val updateDependencyLocks by tasks.registering {
 }
 
 val allDependencies by tasks.registering(DependencyReportTask::class)
+
+tasks.withType(Test::class).configureEach {
+  System.getProperty("testReportsDir")?.let { reportsDir ->
+    reports.junitXml.outputLocation.set(file(reportsDir).resolve(project.name).resolve(name))
+  }
+  debugOptions {
+    enabled = System.getProperty("jvmdebug")?.toBoolean() ?: false
+    @Suppress("UnstableApiUsage")
+    host = "*"
+    port = 5005
+    suspend = true
+    server = true
+  }
+}
+
+tasks.withType(JavaExec::class).configureEach {
+  debugOptions {
+    enabled = System.getProperty("jvmdebug")?.toBoolean() ?: false
+    @Suppress("UnstableApiUsage")
+    host = "*"
+    port = 5005
+    suspend = true
+    server = true
+  }
+}