Replace our own stanza_get_child_by_name_and_ns() with the upstreamed
xmpp_stanza_get_child_by_name_and_ns() provided by the new
libstrophe/libmesode 0.10.0.
Discovering Public Keys via PEP
* 4.3 Discovering Public Keys of a User
* 4.4 Requesting Public Keys
* Import Public Keys into GnuPG's local keyring.
Issue: #1331
src/pgp/gpg.c:p_ox_gpg_readkey
Used to read a public key from a file. The function will return the fingerprint
of the file and the base64 encoded key.
src/xmpp/ox.[hc]
ox_announce_public_key(const char* const filename) can be called from the /ox
announce <filename> command. The key within the file will be pushed on PEP and
the Metadata node will be set.
Issue: #1331
