- Create install/export for targets for super-projects + related fixes
- Patch upstream miniupnpc build + temporarily update local submodule URL/branch
- Allow Makefile to set CMAKE_INSTALL_PREFIX
- Move path detection into CMake + related fixes
- kovri-install: allow super-projects to set root/build
  * This is required for super-projects which are installing via their CMake
    (via *their* build and paths).

Note: Crypto++ doesn't build when we try to build with CMake in super-projects.
However, Crypto++ *will* build if done locally.