package.json: fix license declaration

This now lists all licenses contained in the build by SPDX-identifiers,
using regular 'NTP' for Debian's 'NTP~disclaimer' as it lacks a SPDX-ID.

The actually important part is at the start; since all other licenses
don't add any new requirements, effectively the short version is:
  GPL-2+ OR (LGPL-2.1+ AND FTL)

package.json

@@ -21,7 +21,7 @@
     "emscripten"
   ],
   "author": "TFSThiagoBR98, Dador",
-  "license": "MIT",
+  "license": "LGPL-2.1-or-later and (FTL OR GPL-2.0-or-later) AND MIT AND MIT-Modern-Variant AND ISC AND NTP AND Zlib AND Apache-2.0",
   "bugs": {
     "url": "https://github.com/Dador/JavascriptSubtitlesOctopus/issues"
   },