Rename "io.netty.recycler.maxCapacity.default" to "io.netty.recycler.maxCapacity"

Motivation:

'io.netty.recycler.maxCapacity.default' is the only property for recycler's default maximum capacity, so having the 'default' suffix only increases the length of the property name.

Modifications:

Rename "io.netty.recycler.maxCapacity.default" to "io.netty.recycler.maxCapacity"

Result:

Shorter system property name. The future addition of system properties, such as io.netty.recycler.maxCapacity.outboundBuffer, are not confusing either.