mod_cluster load metric capacity and weight defaults are wrong

The context of the capacity of a load metric is metric-specific. The default capacity values should be defined per-metric, or at least default to 1.
Also, the weight of a metric should default to 1, not 9.
Additionally, the defaults for load history should default to something reasonable (e.g. 10), not 512; same for decay factor (2, instead of 512).
Also, capacity should expect a double, not an integer. This is important, since many load metrics represent their load values as decimal values between 0 and 1.