Regress a few changes from this branch until unix socket support is fully embraced —
* Maintain current keosd *-server-address config names
* Have keosd start HTTP server by default still (though this time on 8900)
* Change cleos default URL back to http://127.0.0.1:8900

Also add customization method for defaults based on nodeos vs keosd

Add optional Mac App Store signing for nodeos & keosd. Mac App Store style signing is required to use the Secure Enclave. Four new parameters must be given to cmake to enable this feature (MAS_CERT_FINGERPRINT, MAS_BASE_APPID, MAS_PROVISIONING_PROFILE, and MAS_KEYCHAIN_GROUP)

The final MAS signed app file is not currently included in the cpack configuration.