Kwcoco

Fixed
* Fix broken paths in camvid converter
* fixed issues when converting segmentations to legacy mscoco format
* Issue with `image_filepath` in CocoImage / CocoAsset

Added
* Added `CocoDataset.add_categories`
* Users can now specify sensorchan for toydata videos to get a custom sensor/channel arrangement
* Added `flatten` method to `ObjectGroups`.
* Add public `rebuild_index` function which should be used instead of `_build_index`.

Changed
* Set verbose default of reroot to 0 to match documentation.
* `rich` is now a runtime requirement.

Changed

* Changed `visual_stats` to `plot_stats`.
* Moved kw18 and kpf to a new `formats` submodule.
* kwcoco show now respects video frame order if available
* modified scheme so supercategory is now allowed to be an empty string

Added

* Added basic helpers for converting from labelme and voc annotations
* Added finish-install helper script.

Added
* New `load` classmethod (analogous to `dump`) as a placeholder for a potential
future refactor.
* Ported segmentation metrics from geowatch. Eventually metrics may be ported
to a new package: kwmetrics in order to improve modularity and keep
components well-scoped.
* Added `out_fpath` to `coco_eval` CLI signature.
* Added `video_ids` argument to `CocoDataset.subset`
* Added `.objs_iter()` method to `ObjectList1D` as an alternative to `.objs`
* Added `.get_iter(...)` method to `ObjectList1D` as an alternative to `.get(...)`
* Added `.coco_images_iter()` method to `Images` as an alternative to `.coco_images`
* `kwcoco/cli/coco_visual_stats.py`

Changed
* `CocoDataset.add_track` will now pick a name using a uuid if one is unspecified.
* Added more metrics to outputs in coco eval
* demodata can now be populated with random timestamps
* dict proxy items can now use the pop and delitem methods
* scriptconfig CLI interfaces have been modernized.

Fixed
* CIFAR grabdata now respects dpath
* `CocoDataset.ensure_video` properly checks for duplicate video names now.

Fixed
* Handle deprecated `scipy.integrate.trapz`

Fixed

* CIFAR grabdata now converts train and test variants of the dataset and
includes channel information.

Removed
* Drop 3.6 and 3.7 support

Changed
* Optimize CocoObject1D get calls with SQL backends
* CocoObject1D.lookup with default now "works"-ish with SQL. Still experimental.

Fixed

* Added workaround for an issue where a postgresql cache of a coco dataset is unable to remember its original json filepath.
* Fixed issue with `CocoSqlDatabase.disconnect` where a session would be dereferenced, but not closed.
* Worked around issue in postgresql backend where track-ids were not decoded properly in their string form.