Fix revive package stuttering errors

- Rename SecretMetadata to Metadata in secret package
- Rename SecretVersion to Version in secret package
- Update NewSecretVersion to NewVersion function
- Update all references across the codebase including:
  - vault package aliases
  - CLI usage
  - test files
  - method receivers and signatures

TODO.md

@@ -6,6 +6,11 @@ prioritized from most critical (top) to least critical (bottom).
 
 ## Code Cleanups
 
+* none of the integration tests should be searching for a binary or trying
+  to execute another process.  the integration tests cannot make another
+  process or depend on a compiled file, they must do all of their testing in
+  the current (test) process.
+
 * we shouldn't be passing around a statedir, it should be read from the
   environment or default.