Add check for mssqlserver memory requirements

[wadjoh]

When I was working on getting this module setup in my tests I kept running into a super generic error that I wasn't getting with the MySQL module:

org.testcontainers.containers.ContainerLaunchException: Container startup failed
	at org.testcontainers.containers.GenericContainer.start(GenericContainer.java:189)

I had to manually start up up a container with the mssqlserver image to see the error message:

sqlservr: This program requires a machine with at least 3250 megabytes of memory.

Which then pointed me in the right direction: My macOS Docker only had 2 GB dedicated to it. Upping to 3.5 GB solved the probem.

Would it be possible to check that Docker has access to a sufficient amount of memory before trying to start up the MS SQL Server container?