add dynamic flask example

[akaszynski]

This PR adds a dynamic flask example to supplement the existing static example and resolves #2459.

127.0.0.1_5000.mp4

[codecov]

Codecov Report

Merging #2552 (a1592a0) into main (f1f4df2) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #2552      +/-   ##
==========================================
- Coverage   93.72%   93.69%   -0.03%     
==========================================
  Files          75       75              
  Lines       16120    16160      +40     
==========================================
+ Hits        15108    15141      +33     
- Misses       1012     1019       +7     

[tkoyama010]

Thanks for the addition. I have been waiting for this feature plotting PyVista dynamic in html. I'm not very familiar with flask, but is it necessary not to keep the static example?

[akaszynski]

I'm not very familiar with flask, but is it necessary not to keep the static example?

I guess I didn't do a good job explaining this in the documentation, but the static example is still there. I'll update the docs and potentially rename the directories.

[tkoyama010]

Oh sorry. It's my fault. In that way LGTM.