Add pkl project package --install to local cache (#1795)

docs/modules/pkl-cli/pages/index.adoc

@@ -670,6 +670,12 @@ Example: `--test-reporter minimal` +
 Which test reporter to use for CLI output. Possible values are `spec` and `minimal`.
 ====
 
+.--install
+[%collapsible]
+====
+Install the built package into the module cache dir.
+====
+
 This command also takes <<common-options,common options>>.
 
 [[command-project-resolve]]

docs/modules/pkl-gradle/pages/index.adoc

@@ -694,6 +694,13 @@ Example: `reporter = "minimal"` +
 Which test reporter to use for CLI output. Possible values are `"spec"` and `"minimal"`.
 ====
 
+.install: Property<Boolean>
+[%collapsible]
+====
+Default: `false` +
+Install the built package into the module cache dir.
+====
+
 Common properties:
 
 include::../partials/gradle-common-properties.adoc[]