Replace ProgressMeter with logging

[fgasdia]

By default, a ProgressMeter prints when propagating a SegmentedWaveguide.

Problems:

• There is a higher level ProgressMeter printed when running a collection of SegmentedWaveguides, but it is not shown until the entire collection is complete.
• In fact, ProgressMeters cannot currently be "stacked" with multiple levels of progress, and even if they could be, the user code would need to interact with LongwaveModePropagator's ProgressMeter objects.
• When estimating with LongwaveModePropagator, there will be many, many progress bars printed. This crowds the console and the user cannot use their own ProgressMeter to monitor overall progress.

The ProgressMeter should probably be replaced with Logging utilities. See e.g. MicroLogging.jl, LoggingExtras.jl, TerminalLoggers.jl, or ProgressLogging.jl.

[fgasdia]

There is a display_progress keyword to disable the progress meter, but it is best left up to the user to use a ProgressMeter in their application if they wish.