Conditional beans include support in commons-spring

[mhawryluk]

Issue #431

Makes it possible to include some config only if specified feature flag is enabled. The position of the conditionals list in the file doesn't matter, it will always overwrite other definitions in the file if condition is true. The order of conditional objects in the conditionals list does matter, the latter will possibly overwrite the former.

beans {
  ...
}

conditionals = [
  {condition: ${ump.feature.enabled}, config: {include "feature.conf"}},
  {condition: ${ump.coolStuff.enabled}, config: {x = 2}}
]