Re-license several more files under MPL-2.0

- Several files where @MCJack123 is the exclusive contributor. He has
   signed over all contributions to "any OSI-approved license". Thank
   you!

 - Various the file handle classes: Looking at these again, I don't
   think they contain any of the original code.

projects/web/src/styles.css

@@ -1,8 +1,8 @@
 /*
-SPDX-FileCopyrightText: 2020 The CC: Tweaked Developers
-
-SPDX-License-Identifier: LicenseRef-CCPL
-*/
+ * SPDX-FileCopyrightText: 2020 The CC: Tweaked Developers
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ */
 
 :root {
     --nav-width: 250px;