[analytics] reporting API

[pq]

Migrates API from the flutter plugin (and refines it).

Still TODO, the actual communication (See UnifiedAnalyticsReporter.process(..)).

Once implemented, instrumentation of an action (for example, DartPubActionBase), will look like this:

  override fun actionPerformed(e: AnActionEvent) {
    val (module, pubspecYamlFile) = getModuleAndPubspecYamlFile(e) ?: return

    Analytics.report(AnalyticsData.forAction(this, e))
    performPubAction(module, pubspecYamlFile, true)
  }

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