Add possibility to log things only once or a few times

Following allpix-squared/allpix-squared!256 (merged), adding the same features here:

Now the following commands are available for sending messages to the logging system at a level of LEVEL:

• LOG(LEVEL)
  Send a message with severity level LEVEL to the logging system.

  LOG(LEVEL) << "this is an example message with an integer and a double " << 1 << 2.0;

  A new line and carriage return is added at the end of every log message. Multi-line log messages can be used by adding new line commands to the stream. The logging system will automatically align every new line under the previous message and will leave the header space empty on new lines.

• LOG_ONCE(LEVEL)
  Same as LOG, but will only log this message once over the full run, even if the logging function is called multiple times.

  LOG_ONCE(INFO) << "This message will appear once only, even if present in every event...";

  This can be used to log warnings or messages e.g. from the run() function of a module with out flooding the log output with the same message for every event. The message is preceded by the information that further messages will be suppressed.

• LOG_N(LEVEL, NUMBER)
  Same as LOG_ONCE but allows to specify the number of times the message will be logged via the additional parameter NUMBER.

  LOG_N(INFO, 10) << "This message will appear maximally 10 times throughout the run.";

  The last message is preceded by the information that further messages will be suppressed.

• LOG_PROGRESS(LEVEL, IDENTIFIER)
  This function allows to update the message to be updated on the same line for simple progressbar-like functionality.

  LOG_PROGRESS(STATUS, "EVENT_LOOP") << "Running event " << n << " of " << number_of_events;

  Here, the IDENTIFIER is a unique string identifying this output stream in order not to mix different progress reports.