Validate certs parameter for JDBC driver downloads

[InfoSec812]

• Added jdbc_download customization to both keycloak releases
• Added option to allow invalid certificates to download JDBC drivers

keycloak_quarkus:

Variable	Description	Required
keycloak_quarkus_jdbc_download_url	Override the default Maven Central download URL for the JDBC driver	no
keycloak_quarkus_jdbc_download_user	Set a username with which to authenticate when downloading JDBC drivers from an alternative location	no
keycloak_quarkus_jdbc_download_pass	Set a password with which to authenticate when downloading JDBC drivers from an alternative location (requires keycloak_quarkus_jdbc_download_user)	no

keycloak:

Variable	Description	Required
keycloak_jdbc_download_url	Override the default Maven Central download URL for the JDBC driver	no
keycloak_jdbc_download_user	Set a username with which to authenticate when downloading JDBC drivers from an alternative location	no
keycloak_jdbc_download_pass	Set a password with which to authenticate when downloading JDBC drivers from an alternative location (requires keycloak_quarkus_jdbc_download_user)	no

Resolves #206

I was able to test for keycloak_quarkus, but not for keycloak.

[guidograzioli]

looking good