fix(did_parser): Add readme and simple example (openwallet-foundation#1047)

Author: xprazak2

did_parser/README.md

@@ -0,0 +1,3 @@
+# did_parser
+
+A crate for parsing DIDs and DID URLs.

did_parser/examples/did_parser/main.rs

@@ -0,0 +1,10 @@
+use did_parser::{Did, DidUrl};
+
+fn main() {
+    // parse a string into DID
+    Did::parse("did:web:w3c-ccg.github.io".into()).expect("should correctly parse did");
+
+    // parse a string into DID URL
+    DidUrl::parse("did:example:123456789abcdefghi;param=value?query=value".into())
+        .expect("should correctly parse did url");
+}