* compat: remove bswap_* check on macOS
This was originally added in #9366 to fix the gui build, as
Protobuf would also define these macros. Now that we're no-longer
using Protobuf, remove the additional check.
* build: skip building OpenSSL lib_ssl
* build: remove OpenSSL from Qt build
More info available from:
https://doc.qt.io/qt-5/ssl.html#enabling-and-disabling-ssl-support
* build: remove EVP_MD_CTX_new detection
This was added in #9475 to fix LibreSSL compatibility for
BIP70, so is no longer required.
* build: remove SSL lib detection
* gui: update BIP70 support message
* build: remove BIP70 entries from macOS Info.plist
* gui: remove payment request file handling from OpenURI dialog
* gui: remove BIP70 Support
* build: remove protobuf from depends and contrib
