add option to prevent Gradle plugin from adding dependency on KSP

We add plugin automatically for better onboarding experience, but it makes project depend on some specific KSP version. KSP complains when people use it with different version of compiler:
ksp-1.9.0-1.0.12 is too old for kotlin-1.9.21. Please upgrade ksp or downgrade kotlin-gradle-plugin to 1.9.0.
In dataframe project itself we always need to update Kotlin version in two steps. With this change (and one more PR later) it won't be necessary anymore

Still, it's ok to use preprocessor built for 1.9.0 with KSP 1.9.21. That's why we need an option for people to decide version of KSP they need in their project.
People will be able to use our preprocessor built for older versions of KSP API most of the time without problems thanks to backward compatibility

Author: koperagen

plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/ConvenienceSchemaGeneratorPlugin.kt

@@ -3,13 +3,29 @@ package org.jetbrains.dataframe.gradle
 import com.google.devtools.ksp.gradle.KspExtension
 import org.gradle.api.Plugin
 import org.gradle.api.Project
-import org.gradle.kotlin.dsl.getByType
+import org.gradle.kotlin.dsl.findByType
 import java.util.*
 
 @Suppress("unused")
 class ConvenienceSchemaGeneratorPlugin : Plugin<Project> {
     override fun apply(target: Project) {
-        target.plugins.apply(KspPluginApplier::class.java)
+        val name = "kotlin.dataframe.add.ksp"
+        val property = target.findProperty(name)?.toString()
+        var addKsp = true
+
+        if (property != null) {
+            if (property.equals("true", ignoreCase = true) || property.equals("false", ignoreCase = true)) {
+                addKsp = property.toBoolean()
+            } else {
+                target.logger.warn("Invalid value '$property' for '$name' property. Defaulting to '$addKsp'. Please use 'true' or 'false'.")
+            }
+        }
+        if (addKsp) {
+            target.plugins.apply(KspPluginApplier::class.java)
+        }
+        target.afterEvaluate {
+            target.extensions.findByType<KspExtension>()?.arg("dataframe.resolutionDir", target.projectDir.absolutePath)
+        }
         target.plugins.apply(SchemaGeneratorPlugin::class.java)
     }
 }
@@ -31,6 +47,5 @@ internal class KspPluginApplier : Plugin<Project> {
         target.configurations.getByName("ksp").dependencies.add(
             target.dependencies.create("org.jetbrains.kotlinx.dataframe:symbol-processor-all:$preprocessorVersion")
         )
-        target.extensions.getByType<KspExtension>().arg("dataframe.resolutionDir", target.projectDir.absolutePath)
     }
 }