Use Ipython display for image rendering

[JarnoRFB]

And refactor artifacts completely.

[codecov]

Codecov Report

Merging #25 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #25   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           4      4           
  Lines         229    209   -20     
=====================================
- Hits          229    209   -20

Impacted Files	Coverage Δ
incense/artifact.py	100% <100%> (ø)	⬆️
incense/experiment.py	100% <100%> (ø)	⬆️

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