ktrace: Record detailed ECAPMODE violations

When a Capsicum violation occurs in the kernel, ktrace will now record
detailed information pertaining to the violation.

For example:

• When a namei lookup violation occurs, ktrace will record the path.
• When a signal violation occurs, ktrace will record the signal number.
• When a sendto(2) violation occurs, ktrace will record the recipient sockaddr.

For all violations, the syscall and ABI is recorded.

kdump is also modified to display this new information to the user.

Reviewed by: oshogbo, markj
Approved by: markj (mentor)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D40676