NoIssue: Add Checksum tag and SHA256 valuetype

src/main/java/com/r35157/libs/valuetypes/basic/Checksum.java

@@ -0,0 +1,8 @@
+package com.r35157.libs.valuetypes.basic;
+
+/**
+ * Checksum is the super tag for all kinds of checksum value types.
+ */
+
+public interface Checksum {
+}

src/main/java/com/r35157/libs/valuetypes/basic/SHA256Checksum.java

@@ -0,0 +1,11 @@
+package com.r35157.libs.valuetypes.basic;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Id is the super tag for all kinds of id value types.
+ */
+
+public record SHA256Checksum (
+    @NotNull String value
+) implements Checksum {}