Provide properties for configuring JDBC connections with SSL

[scottfrederick]

[scottfrederick]

Configuring SSL for JDBC connections is not as seamless as it is for the other client connection libraries that have been enhanced with support for Spring Boot SSL bundles. Most JDBC drivers require certificates to be provided as files, not as an SSLContext, SSLSocketFactory or other Java object that can be derived from certificates and private keys and passed to an API.

The table below shows the configuration options available for JDBC drivers.

JDBC driver	SSL configuration
PostgreSQL	JDBC URL parameters sslfactory to provide a custom SSLSocketFactory implementation class name, or sslcert, sslkey, sslrootcert to provide files
MySQL	javax.net.ssl.* system properties or Connector/J connection properties to provide DER-encoded files
MariaDB	serverSslCert JDBC URL parameter to provide PEM file or DER-encoded string value
Oracle	javax.net.ssl.* system properties to provide JKS files
SQL Server	javax.net.ssl.* system properties to provide JKS files

Given the current landscape, we do not think it is feasible at this time to provide properties under spring.datasource that would only map cleanly to PostgreSQL, as we don't want to add properties that would only be effective for one driver. We'll put this issue on hold for now.