Installed builds of the Engine cannot package game targets with optional game features

The build system supports many types of flags that can be enabled in game-specific Target.cs files to enable things like logging in shipping, target-specific overrides like custom config, or enabling plugins for a certain release version. These features depend on having a unique build environment, but in an installed/Rocket version of the engine it will always use the Shared build environment for monolithic builds (so it can reuse the intermediate binaries we ship). This issue is also why you cannot package Test versions or dedicated servers using an installed build. This restriction exists in both launcher-downloaded versions of the engine as well as custom licensee-built installer versions.

Newer samples like Lyra heavily take advantage of these features to support creating a modular game that can be configured at target creation time. These features need to be disabled or hacked around to work with installed builds. Also the warning messages for these features tend to say things like "use a monolithic build" when the tool is already trying to create a monolithic build so it is confusing to end users 

It makes sense for a blueprint-only game to use the shared monolithic environment, but there needs to be some way for a C++ game to opt in to requiring a unique build environment when creating monolithic builds. Packaging C++ games already requires a working compiler so it could recompile the engine binaries at the same time. Trying to reuse the intermediate binaries in packaged builds is not worth the complication because monolithic versions of a game are much faster to compile than the entire editor is.

1. Install the 5.0 version of the engine from the Launcher
2. Download Lyra from the Launcher as well
   • Note that this may only be available in the GameDev environment
3. Open Lyra in editor
4. Go to the Platforms drop down, select Windows, then LyraGameEOS to set to that target
5. Go back to platforms, windows, package project and pick a directory
6. The packaging process will fail with an error about shared build environments with the warning "LyraGameEOS and dynamic target options are disabled when packaging from an installed version of the engine" in the log above it

LyraGameEOS will package fine from a custom version of the engine, but can not work with installed versions which the warning explains