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>

.circleci/config.pkl

@@ -14,7 +14,7 @@
 // limitations under the License.
 //===----------------------------------------------------------------------===// 
 // File gets rendered to .circleci/config.yml via git hook.
-amends "package://pkg.pkl-lang.org/pkl-project-commons/pkl.impl.circleci@1.1.0#/PklCI.pkl"
+amends "package://pkg.pkl-lang.org/pkl-project-commons/pkl.impl.circleci@1.1.1#/PklCI.pkl"
 
 import "jobs/BuildNativeJob.pkl"
 import "jobs/GradleCheckJob.pkl"
@@ -96,6 +96,11 @@ local buildNativeJobs: Mapping<String, BuildNativeJob> = new {
       musl = true
       isRelease = _dist == "release"
     }
+    ["pkl-cli-windows-amd64-\(_dist)"] {
+      arch = "amd64"
+      os = "windows"
+      isRelease = _dist == "release"
+    }
   }
 }
 
@@ -108,6 +113,11 @@ local gradleCheckJobs: Mapping<String, GradleCheckJob> = new {
     javaVersion = "21.0"
     isRelease = false
   }
+  ["gradle-check-jdk17-windows"] {
+    javaVersion = "17.0"
+    isRelease = false
+    os = "windows"
+  }
 }
 
 jobs {