Use a newer version of uVisor that doesn't change the box main thread
function type. Previously, we required all box main thread definitions
to change from taking a `const void *` to a `void *` when moving to
RTX5. We now are backwards compatibile.
* Updated docs
* Re-factored vMPU drivers
* Non-backwards-compatible API change: uvisor_ctx is now called
__uvisor_ctx and requires the user to explicitly cast it to their own
private context structure.
This only affects applications with uVisor enabled.
* Use "public box" instead of main box for box 0.
- Enhanced Debug Box
- Allow hw-specific ACL extensions per region
- Reduce background region rights to debugger and core
- Added Beetle SoC uVisor support
- MPU code restructured
Jaeden Amero
Bartek Szatkowski
Alessandro Angelino
Milosch Meriac