Improve our logging system

[manuroe]

We need to have a more advanced logging system than the basic NSLog() in MatrixSDK, MatrixKit, Element-iOS where:

• We have classic debug levels like verbose, debug, warn, error. We can use debug() everywhere during the transition step and affine latter.
• We continue to log to files (those files are sent to the rageshake server):
  • log files dedicated to the app and to every extension (Siri, sharing, notification service)
  • a file per life cycle
• We need to keep the same kind of circular log system as today where we can select the max number of log files (like 50) and their max size (like 100MB)
• We can select logging output at build time and runtime: to file, to device console, to both or to none (disable logs)
• Log output is very similar to the current NSLog output. We need timestamp and thread id.
• Improve logging by module. We currently use this pattern : NSLog(@"[MyClass] xxxx") to separate them. This is boring to repeat [MyClass] on every log
• It should be implemented in swift but usable from objc. We could have a bridge object between objc and the final swift tool to avoid to loose swift power when we are all full swift.

We should have a weak dependency on the logging lib we will use. We could probably reuse the MXLogger object.