Reintroduce Clitk extensions module

A future commit will introduce CLI options that need to be interpreted
as an Instant.

Signed-off-by: Graham <gpe@openrs2.org>

cli/build.gradle.kts

@@ -0,0 +1,24 @@
+plugins {
+    `maven-publish`
+    kotlin("jvm")
+}
+
+dependencies {
+    api("com.github.ajalt.clikt:clikt:${Versions.clikt}")
+}
+
+publishing {
+    publications.create<MavenPublication>("maven") {
+        from(components["java"])
+
+        pom {
+            packaging = "jar"
+            name.set("OpenRS2 CLI")
+            description.set(
+                """
+                Clikt extensions.
+            """.trimIndent()
+            )
+        }
+    }
+}

cli/src/main/kotlin/org/openrs2/cli/OptionExtensions.kt

@@ -0,0 +1,17 @@
+package org.openrs2.cli
+
+import com.github.ajalt.clikt.core.BadParameterValue
+import com.github.ajalt.clikt.parameters.options.NullableOption
+import com.github.ajalt.clikt.parameters.options.RawOption
+import com.github.ajalt.clikt.parameters.options.convert
+import java.time.Instant
+import java.time.OffsetDateTime
+import java.time.format.DateTimeParseException
+
+public fun RawOption.instant(): NullableOption<Instant, Instant> = convert({ "TIMESTAMP" }) {
+    try {
+        OffsetDateTime.parse(it).toInstant()
+    } catch (ex: DateTimeParseException) {
+        throw BadParameterValue("$it is not a valid timestamp")
+    }
+}

settings.gradle.kts

@@ -6,6 +6,7 @@ include(
     "asm",
     "buffer",
     "cache",
+    "cli",
     "compress",
     "compress-cli",
     "conf",