Modernize SSL support to include per-connector SSLContext, pkcs12 default, keyalias support.

[mattrpav]

• Migrate from ThreadLocal by default
• Default to prefer pkcs12 keystore type
• Support automatic JKS keystore type fallback
• Support keyAlias
• Support SSLContext per-transportConnector, per-networkConnector with broker-wide fallback
• Prepare for reload support

ref: AMQ-9753
ref: AMQ-9694