add all licenses to build output and use them in the app "about"

[ski7777]

Coming from this discussion: https://github.com/ftCommunity/ftcommunity-TXT/commit/c3b710e7a6249a09e71b775c242a509c52a7ba13#commitcomment-92551986 I would suggest, using buildroot to generate a full legal notice bundle and pack it into the rootfs. Here we can use it in the about app

[ski7777]

postponing to 1.1