cli: refactor progress indication

cli: refactor progress indication

This patch:

  * Increases the encapsulation of the different progress
    indicators: the progress code does not access its
    owner's attributes anymore
  * Makes the progress update at most every 100 ms
  * Makes the progress indication use the current timestamp
    and the trace collection's begin/end timestamps to
    approximate its position; falls back on approximating
    with the size if those timestamps are not available
  * Adds the general --progress-use-size CLI option to
    reverse to the old default behaviour of approximating
    with the size

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>