feat: measure configuration phase duration

[wzieba]

Description

This PR adds a new metric, configuration-duration, to measure time spent on initialization and configuration of Android builds.

How does it work?

If project#afetEvaluate is executed, it means that the configuration phase was executed. Then, ConfigurationPhaseObserver#init is called and ConfigurationPhaseObserver#obtain returns true, and resets its internal state to false immediately after.

If project#afetEvaluate is not executed, it means that the build used the Configuration Cache feature. Because we reset the internal state of ConfigurationPhaseObserver to false, it will return false in case of being retrieved from Configuration Cache, giving the expected result.

The value of Configuration Phase duration is calculated via subtracting the build initiation time, provided by BuildStartedTime, and build start time, assigned in constructor of BuildTaskService.