tuih shuld be able to specify the output file name, and not rely on pre-test command line flag --tui-htmlfile

[jeffwright13]

In fact, consider removing that cmd line option entirely. But think carefully of user workflow:

• pytest --tui (generates ptt_files/ artifacts)
• tuih --nondefault-html-location

I keep going back and forth on the whole auto-launch-braowser issue. Right now I'm currently thinking the way to do it is to generate the html file by default, in the default location, but do not autolaunch it; that way, user can either launch with "tuih" (specifying non default location if desired), or else just open the default html file manually. However, thiis won't play well with CI use of this lib, since we should not expect a CI train to have to e xecute a command-line tool just to open the file. Hmmm.

I also keep going back and forth on whether or not to bring back the (Bullet-based) visual config tool. It was nice to have and centralized config, but again, takes away from CI usage. And it was a PITA to handle all the different use cases together.