Build: Remove redundant TFM_INSTALL_PATH variable

- Use a standard CMAKE_INSTALL_PREFIX variable instead
- Add default value CMAKE_INSTALL_PREFIX
- Make available install directoy global from local in install.cmake
- Install binaries to /bin instead of /outputs

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: I3b259ac9686af69e98f1b1a4263209ce32eb1324
10 files changed