Added support for collecting model actions and counts

[itsgoingd]

• added support for collecting number of retrieved, created, updated and deleted models
• added support for collecting individual model actions, including model name, primary key, attributes, changes and stack trace
• supported in EloquentDataSource w/ new configuration options (by default collect only counts and update actions)
• Added new "models" tab underground-works/clockwork-app#41

todo

• consider refactoring how we pass options to EloquentDataSource (too many options)
• test with old Laravel versions