This commit changes from a precompiled bundle to
a source file. Accordingly, the expression file is renamed to `default.nix`
and the old attribute name is changed to `tvbrowser`, the old one being now a
throw-message.
The upstream build script tries to download the news plugin; so, we provide
this and pass it as a parameter.
Given that this is still a piece of a precompiled Java bytecode, along with a
main readable source bundle, `meta.sourceProvenance` is updated accordingly.
b2fdba820a