main/dovecot: upgrade to 2.3.14

use 0001-oauth2-jwt-Use-int64_t-instead-time_t-for-portabilit.patch instead of fix-oauth2-jwt.c.patch, posted to me by upstream author

add fix-libssl_iostream_openssl.patch, also posted by upstream author

add prepare() and add autoreconf to it, and add gettext-dev to makedepends, autoreconf need it