These statistics were largely ununsed, and kept track of statistical information
on things like how many time we had done TLS or how many signatures we had
verified.  This information is largely not useful, and would only be logged
after receiving a SIGUSR1 signal (but only if the logging severity level was
less than LOG_INFO).

 * FIXES #19871.
 * REMOVES note_crypto_pk_op(), dump_pk_op(), and pk_op_counts from
   src/or/rephist.c.
 * REMOVES every external call to these functions.