feat(apix): timezone wrapper

Differences from the "stable" api common package one:
 - inline class, no serializer object
 - constructor null param means "auto"
 - companion object with `auto` constant and `getTimeZone`s methods

Author: DadiBit

lib/src/main/kotlin/com/openmeteo/apix/common/time/TimeZone.kt

@@ -0,0 +1,34 @@
+package com.openmeteo.apix.common.time
+
+import kotlinx.serialization.Serializable
+import java.time.ZoneId
+
+/**
+ * A [TimeZone] class wrapper
+ *
+ * Please note that null is used as an internal value to represent the `"auto"` option
+ */
+@Serializable
+@JvmInline
+value class TimeZone private constructor(
+    val id: String = "auto"
+) {
+    constructor(
+        timeZone: java.util.TimeZone? = null
+    ) : this(
+        timeZone?.id ?: "auto"
+    )
+
+    companion object {
+        val auto = TimeZone("auto")
+        fun getTimeZone(id: String) =
+            TimeZone(java.util.TimeZone.getTimeZone(id))
+        fun getTimeZone(id: ZoneId) =
+            TimeZone(java.util.TimeZone.getTimeZone(id))
+    }
+
+    val timeZone: java.util.TimeZone?
+        get() = java.util.TimeZone.getTimeZone(id)
+
+    override fun toString(): String = id
+}