MINOR: initcall: use initcalls for most post_{check,deinit} and per_thread*

MINOR: initcall: use initcalls for most post_{check,deinit} and per_thread*

Most calls to hap_register_post_check(), hap_register_post_deinit(),
hap_register_per_thread_init(), hap_register_per_thread_deinit() can
be done using initcalls and will not require a constructor anymore.
Let's create a set of simplified macros for this, called respectively
REGISTER_POST_CHECK, REGISTER_POST_DEINIT, REGISTER_PER_THREAD_INIT,
and REGISTER_PER_THREAD_DEINIT.

Some files were not modified because they wouldn't benefit from this
or because they conditionally register (e.g. the pollers).