MINOR: tools: also implement ha_aligned_alloc_typed()

MINOR: tools: also implement ha_aligned_alloc_typed()

This one is a macro and will allocate a properly aligned and sized
object. This will help make sure that the alignment promised to the
compiler is respected.

When memstats is used, the type name is passed as a string into the
.extra field so that it can be displayed in "debug dev memstats". Two
tiny mistakes related to memstats macros were also fixed (calloc
instead of malloc for zalloc), and the doc was also added to document
how to use these calls.