Hardcoded defaults for systemUsage not suitable for out of the box

Right now the default activemq.xml has the entire <systemUsage> section commented out. If commented, then the default systemUsage as defined in BrokerService.getSystemUsage() applies and uses these limits:

memoryLimit 64 MB
storeLimit: 10 GB
tempLimit: 100 GB

I don't think these are good default values as in the worst case the broker may use 110 GB of disk space. Many runtime environments will not have that much disk space and are therefore in danger of running out of disk space completely.
IMHO some more sensitive defaults would be

memoryLimit 64 MB
storeLimit: 1 GB
tempLimit: 1 GB

to prevent the broker from using too much disk space by default.
I believe most users of ActiveMQ are unaware of these defaults and probably don't expect the broker to use up to 110 GB of their disk.

If anyone really needs large store and temp limit, they should explicitly configure for it.