debug: Remove catchsegv and libSegfault (BZ #14913)

Trapping SIGSEGV within the process is error-prone, adds security
issues, and modern analysis design tends to happen out of the
process (either by attaching a debugger or by post-mortem analysis).

The libSegfault also has some design problems, it uses non
async-signal-safe function (backtrace) on signal handler.

There are multiple alternatives if users do want to use similar
functionality, such as sigsegv gnulib module or libsegfault.