dev(hansbug): optimize graphviz visualization

[HansBug]

Description

1. Add svg render support for TreeValue objects.
2. Fix text align problem on multiple-line objects (such as np.ndarray and torch.Tensor).

See: https://colab.research.google.com/drive/1xEnnpkfEMbK70guWY0Gwq3ikgsaLvszo

Check List

• merge the latest version source branch/repo, and resolve all the conflicts
• pass style check
• pass all the tests

[codecov]

Codecov Report

Merging #75 (576dea7) into main (947e137) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main      #75   +/-   ##
=======================================
  Coverage   99.00%   99.01%           
=======================================
  Files          43       43           
  Lines        2726     2751   +25     
=======================================
+ Hits         2699     2724   +25     
  Misses         27       27           

Flag	Coverage Δ
unittests	99.01% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
treevalue/tree/tree/graph.py	100.00% <100.00%> (ø)
treevalue/tree/tree/tree.pyx	99.32% <100.00%> (+0.02%)	⬆️
treevalue/utils/tree.py	100.00% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.