Added 'LuaRocks' Dependency

[sage-etcher]

Runner doesn't include the LuaRocks alien tree if LuaRocks isn't listed as a dependency. This means that if a dependency like LuaRocks:MODULE_NAME needs to be accessible at build time, the build may fail.

This can be seen directly when trying to compile Awesome 4.3, which requires LuaRocks:lgi. As encountered in Recipes issue#128.

[hishamhm]

In an ideal world, rather than adding every language package manager as a dependency for Compile, Compile could derive that a Dependency of the kind Foo:bar means that package manager Foo is an implicit BuildDependency.

But since Awesome and by extension Lua are already in the default base system, just adding LuaRocks as a dependency here wouldn't be too problematic.

[sage-etcher]

In an ideal world, rather than adding every language package manager as a dependency for Compile, Compile could derive that a Dependency of the kind Foo:bar means that package manager Foo is an implicit BuildDependency.

Assuming all goes accordingly, it doesnt look too difficult to implement in FindDependencies.c. I'll look into doing such =DD