Add string utils object with basic string operations

Author: raf-nr

ksmt-core/src/main/kotlin/io/ksmt/utils/StringUtils.kt

@@ -0,0 +1,11 @@
+package io.ksmt.utils
+
+import io.ksmt.expr.KStringLiteralExpr
+
+object StringUtils {
+
+    @JvmStatic
+    fun concatStrings(lhs: KStringLiteralExpr, rhs: KStringLiteralExpr): KStringLiteralExpr = with (lhs.ctx) {
+        mkStringLiteral(lhs.value + rhs.value)
+    }
+}