Provides a configuration option for enabling HDCR.TD* traps, or saving and loading debug
state on VCPU switches. Currently verification only plans to support the trap setting.
As this option complicates all of the #ifdef's related to debug registers even further,
abstractions for enabling/disabling each individual piece of the debug code for different
configuration options are also implemented.
Part of these refactored #ifdef guards was to remove the guards completely from libsel4
around the definitions of the number of breakpoints and watchpoints.