AuditService (#2)

* Add AuditService.

* Change sha1 to use Webcrypto.

* Add interface for AuditService.

* Move PwnedPasswodsApi constant outside class.

* Change FromBufferToHex implementation to simpler code.

* Use correct string to array function.

* Change auditService interface to abstract class. Add missing type to utils.

src/abstractions/audit.service.ts

@@ -0,0 +1,3 @@
+export abstract class AuditService {
+    passwordLeaked: (password: string) => Promise<number>;
+}