feat: add some mod api calls

- Get Project: Already existed but required a specific caller type. This
  is more general.
- Get Projects: A single call to multiple of the above

Both providers support these calls.

Signed-off-by: flow <flowlnlnln@gmail.com>

launcher/modplatform/helpers/NetworkModAPI.h

@@ -8,6 +8,8 @@ class NetworkModAPI : public ModAPI {
     void getModInfo(CallerType* caller, ModPlatform::IndexedPack& pack) override;
     void getVersions(CallerType* caller, VersionSearchArgs&& args) const override;
 
+    auto getProject(QString addonId, QByteArray* response) const -> NetJob::Ptr override;
+
    protected:
     virtual auto getModSearchURL(SearchArgs& args) const -> QString = 0;
     virtual auto getModInfoURL(QString& id) const -> QString = 0;