#4400, #5462: Move SHA1/HEX helpers to crypto-utils

#4400, #5462: Move SHA1/HEX helpers to crypto-utils

On a way to factoring out OpenSSL support to a standalone file to ease
addition of other crypto libraries support in the future, move helpers
providing SHA1/HEX conversion to crypto-utils.{c,h}.

Rename functions:
* tr_sha1_to_hex -> tr_binary_to_hex (add length argument),
* tr_hex_to_sha1 -> tr_hex_to_binary (add length argument).

Make tr_sha1_to_hex and tr_hex_to_sha1 wrappers around above functions.