bfconvert command line tool: Smarter resolution handling

[dgault]

This request for first raised on the imagesc thread: https://forum.image.sc/t/bfconvert-size-of-smallest-pyramid-level/46282/4

There are 2 main requests from this thread:

• The option to 'smart' create pyramid resolutions when only the option -pyramid-scale. In this scenario the number of resolutions would not be provided by the user. Instead the converter would create resolutions until a sensible base line (proposed as the tile size) is reached.

• To better handle the scenario when too many resolutions are requested and the below exception is thrown: Exception in thread "main" java.lang.IllegalArgumentException: 0 must be non-null and strictly positive