Use warm-boot infrastructure for fast-boot (#11594)

This PR should be merged together with the sonic-utilities PR (sonic-net/sonic-utilities#2286) and sonic-sairedis PR (sonic-net/sonic-sairedis#1100).

Use redis contents from dump file in fast-reboot.

Improve fast-reboot flow by utilizing the warm-reboot infrastructure.
This followes https://github.com/sonic-net/SONiC/blob/master/doc/fast-reboot/Fast-reboot_Flow_Improvements_HLD.md

files/build_templates/docker_image_ctl.j2

@@ -87,7 +87,7 @@ function preStartAction()
 {%- if docker_container_name == "database" %}
     WARM_DIR=/host/warmboot
     if [ "$DATABASE_TYPE" != "chassisdb" ]; then
-        if [[ ("$BOOT_TYPE" == "warm" || "$BOOT_TYPE" == "fastfast")  && -f $WARM_DIR/dump.rdb ]]; then
+        if [[ ("$BOOT_TYPE" == "warm" || "$BOOT_TYPE" == "fastfast" || "$BOOT_TYPE" == "fast")  && -f $WARM_DIR/dump.rdb ]]; then
             # Load redis content from /host/warmboot/dump.rdb
             docker cp $WARM_DIR/dump.rdb database$DEV:/var/lib/redis/dump.rdb
         else
@@ -218,7 +218,7 @@ function postStartAction()
                  ($(docker exec -i database$DEV sonic-db-cli PING | grep -c PONG) -gt 0) ]]; do
           sleep 1;
         done
-        if [[ ("$BOOT_TYPE" == "warm" || "$BOOT_TYPE" == "fastfast") && -f $WARM_DIR/dump.rdb ]]; then
+        if [[ ("$BOOT_TYPE" == "warm" || "$BOOT_TYPE" == "fastfast" || "$BOOT_TYPE" == "fast") && -f $WARM_DIR/dump.rdb ]]; then
             # retain the dump file from last boot for debugging purposes
             mv $WARM_DIR/dump.rdb $WARM_DIR/dump.rdb.old
         else