Update timezone to GMT, reduce SHM requirement to 512M

Increase the SHM to 2048 if you need to support H.264 cameras

utils/docker/phpdate.ini

@@ -1,5 +1,5 @@
 [Date]
 ; Defines the default timezone used by the date functions
 ; http://php.net/date.timezone
-date.timezone = Europe/Amsterdam
+date.timezone = GMT
 

utils/docker/start.sh

@@ -1,8 +1,10 @@
 #!/bin/bash
 
 # Prepare proper amount of shared memory
+# For H.264 cameras it may be necessary to increase the amout of shared memory
+# to 2048 megabytes.
 umount /dev/shm
-mount -t tmpfs -o rw,nosuid,nodev,noexec,relatime,size=2048M tmpfs /dev/shm
+mount -t tmpfs -o rw,nosuid,nodev,noexec,relatime,size=512M tmpfs /dev/shm
 
 # Start MySQL
 /usr/bin/mysqld_safe &