[ENHANCEMENT]: Device assertions in debug mode

[sleeepyjack]

Is your feature request related to a problem? Please describe.

Probing errors can be tedious to debug.
Some of these errors, such as inserting or probing for a sentinel, might even lead to silent failures.

Describe the solution you'd like

Add device-side assertions in debug mode for the following:

• inserting or probing for a sentinel key or payload
• probing took more than capacity-many slots (this will also detect overflow state, i.e., inserting more elements than there are slots in the map)
• out-of-bounds access to storage

assert in device code will impact performance negatively. Thus, I propose we conditionally enable it only if DEBUG is defined.

Describe alternatives you've considered

Instead of using the global DEBUG flag to enable assertions, we could define a new flag CUCO_DEBUG to get finer-grained control.

Additional context

No response