Generalized parser and table for cryptographic materials (eg: certificates)

[directionless]

With pkg/keyidentifier, we've long had the ability to parse private keys. But we've often wanted to add certificates to that. Unfortunately that library and associated table hardcode several assumptions about the shape of the resultant data.

Thus, pkg/cryptoinfo and the associated kolide_cryptoinfo. This is designed to return nested data, suitable for being handed to dataflatten.

Right now, it only parses certificates, though it should handle both common formats (DER and PEM). I think it has the bones to grow into handling all other keys as needed. We could replace pkg/keyidentifier with it.

For example:

osquery> select count(*) from kolide_cryptoinfo where path = '/etc/ssl/cert.pem' ;
+----------+
| count(*) |
+----------+
| 7903     |
+----------+
osquery> select value from kolide_cryptoinfo where path = '/etc/ssl/cert.pem' and fullkey like '%/Subject/CommonName' limit 5;
+-----------------------------------------------------------+
| value                                                     |
+-----------------------------------------------------------+
| Autoridad de Certificacion Firmaprofesional CIF A62634068 |
| Chambers of Commerce Root - 2008                          |
| Global Chambersign Root - 2008                            |
| ACCVRAIZ1                                                 |
| Actalis Authentication Root CA                            |
+-----------------------------------------------------------+