Add detailed tutorials

[SarthakJariwala]

This PR adds detailed tutorials showing different examples :

• Write detailed jupyter notebooks for all different functionalities in seaborn-image

  • General image visualization

  • Image filters - individual, grid and related functions (TO ADD - commentary)

  • Image Distribution --- basic example

  • Working with RGB images

  • Image Grid - multiple images and multi-dimensional image --- basic example

Closes #35

This PR also significantly improves plotting speed by removing tight_layout() from _core.py

[codecov-io]

Codecov Report

Merging #62 into master will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #62      +/-   ##
==========================================
+ Coverage   94.58%   94.64%   +0.05%     
==========================================
  Files           8        8              
  Lines         646      653       +7     
  Branches      156      157       +1     
==========================================
+ Hits          611      618       +7     
  Misses         18       18              
  Partials       17       17              

Impacted Files	Coverage Δ
src/seaborn_image/_core.py	93.22% <ø> (-0.06%)	⬇️
src/seaborn_image/utils.py	91.04% <100.00%> (+1.21%)	⬆️

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