Generalize video and image capture

[blakeNaccarato]

The captures module currently serves boilercv with some module-level constants as defaults and a particular filename scheme. Generalize this approach somewhat, while keeping some sensible defaults (e.g. video format).

• Optimize scale_bool and determine when it is necessary
• Generalize file writing for only MP4 (pyav plugin), TIFF (tifffile_v3 plugin), and PNG (Pillow plugin). Use the v3 API and imopen in the refactor. Allow arguments to be passed through to override behavior, but choose reasonable defaults.
  • Implement MP4 writing with H264. See Image sequence to mp4 / h264 PyAV-Org/PyAV#471 (comment)
  • Implement TIFF writing
  • Implement PNG writing (and JPEG?)
• Do not manipulate paths by default, nor append timestamps. Just raise on improper extension/setting combinations
• Generalize preview_frame behavior to preview arbitrary frames
• Handle boolean-valued arrays consistently in previewing/capturing with scale_bool
• Factor out common compositions of previews/captures to a third module. For example, previewing and capturing at once
• Implement import-time configuration by the consumer with preview/capture flags