Update stitching_utils

[fstur]

Fixes issues #154 #61 #62 and #63.

• The warp function now creates a warped_distance_mask instead of a simple boolean mask, which is then passed to the fuse function. This way, e.g. the fuse_linear function has all the necessary information needed for correct fusion, even if the chunk edge is at an overlapping region.
• Reworked and added fuse functions fuse_linear_random, fuse_overlay_fwd and fuse_overlay_bwd.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 81.02%. Comparing base (1d64e04) to head (d3341d8). Report is 5 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #157 +/- ## ========================================== + Coverage 80.71% 81.02% +0.30% ========================================== Files 35 35 Lines 1659 1686 +27 Branches 235 240 +5 ========================================== + Hits 1339 1366 +27 Misses 314 314 Partials 6 6 ```

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[tibuch]

Awesome :heart_eyes: Thank you @fstur!

Will review as soon as possible (hopefully still today)

[tibuch]

If @imagejan is happy, I am happy too!

Thank you @imagejan for reviewing :shipit:

[fstur]

Thanks, @imagejan for the review. Shall I merge?