Increase default maximum memory for Eclipse ESCET product/runtime

Currently, we set both to 4 GB. This seems low for current systems.

The Steam Hardware & Software Survey: May 2022 indicates:

While I don't know how representative this is for users of Eclipse ESCET, it shows that most people have at least 16 GB. I hence propose to increase it to that. Note that even if a system does not have that amount of memory, it can still be allocated as address space, and starting the Eclipse ESCET IDE will not fail.

Update: we decided to let the JVM decide the maximum available memory, based on the system configuration of the running system. This seems better than any fixed limit.