Notable accumulative changes as compared to our former Rollbar-iOS SDK

• feat: added SwiftPM support (in addition to Cocoapods and Carthage). This is the recommended integration path.
• feat: optional crash reporting module alternatives
• feat: added RollbarPLCrashReporter module
• feat: added RollbarKSCrash module
• feat: explicit reporting of NSErrors
• feat: defined default scrub fields
• refactor: split out RollbarCommon, RollbarNotifier, RollbarDeploys
• refactor: added use of lightweight generics
• refactor: added use nullability attributes
• refactor: removed RollbarConfiguration and replaced it with RollbarConfig
• refactor: changed WhitelistFields into SafeListFields when it comes to the RollbarScrubbingOptions
• refactor: removed all the deprecated API
• refactor: replace NSString-like log level parameters in RollbarLogger interface with RollbarLevel enum
• refactor: replace sync-all log methods of Rollbar and RolbarLogger with ones dedicated to each type of payload: string-message, NSException, NSError, etc.