Updated Keycloak DEVELOPMENT_MAINTENANCE.md section: Modifications made to upstream chart

General MR

Summary

Updates keycloak DEVELOPMENT_MAITENANCE.md.

• Removed add default argument of "-b 0.0.0.0" to bind to localhost this referenced argument was removed from the chart/values.yaml a year ago in MR 87.
• Removed chart/scripts/keycloak.cli \* Quarkus migration: Delete this Wildfly startup config. The referenced keycloak.cli file was deleted a year ago in MR 87.
• Corrected Upstream bitnami postgresql chart - modified for Iron Bank Postgresql 12.9 runtime. The current version is 12.15

Relevant logs/screenshots

(Include any relevant logs/screenshots)

Closes #125 (closed)