This change adds the new boolean property "uploadLock" to the
extension domain model. If the property is set, it is not possible
for an extension author to upload new versions of the extension.
Instead, a message is shown, that the extension author must contact
the TYPO3 Security Team. The upload restriction affects both the
upload using the TER UI and the TER REST API.

This feature is a requirement of the TYPO3 Security Team to prevent
extension authors from uploading new versions of an extension, if
all versions of the extension have been marked as insecure
(which most likely is the case, when the extension author did
not respond on email from the TYPO3 Security Team).

Additionally, usage of `ObjectManager` has been replaced with
dependency injection in `ReviewController`.

Closes #579