feat: add PostgreSQL/MongoDB Images and fix multiarch (#40)

add PostgreSQL/MongoDB Images and fixes multi-arch builds for MariaDB, Redis.

postgres/13/Dockerfile

@@ -0,0 +1,16 @@
+# ----------------------------------
+# Environment: Postgres DB
+# ----------------------------------
+FROM --platform=$TARGETOS/$TARGETARCH postgres:13-alpine
+
+LABEL author="Parker" maintainer="parker@pterodactyl.io"
+
+# UID 999 is the default pterodactyl user
+RUN adduser -D -h /home/container container
+
+USER container
+ENV HOME /home/container
+WORKDIR /home/container
+
+COPY ./entrypoint.sh /entrypoint.sh
+CMD ["/bin/bash", "/entrypoint.sh"]