Feature: move plotting to visuals

[emhbrine]

• This PR migrates most of the plots to /visuals.
• The old functions simply call the new functions in visuals so there should be no change to functionality. Some will be deprecated in the future.
• In the future the many heatmap plots can leverage the Heatmap class. For now only view_metrics uses it.

[codecov]

Codecov Report

Merging #1108 (09c25ce) into develop (7575b7d) will decrease coverage by 0.33%.
Report is 1 commits behind head on develop.
The diff coverage is 51.69%.

❗ Current head 09c25ce differs from pull request most recent head 787bba1. Consider uploading reports for the commit 787bba1 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1108      +/-   ##
===========================================
- Coverage    64.78%   64.46%   -0.33%     
===========================================
  Files           51       54       +3     
  Lines         5299     5465     +166     
===========================================
+ Hits          3433     3523      +90     
- Misses        1866     1942      +76     

Files	Coverage Δ
macrosynergy/panel/view_correlations.py	30.23% <100.00%> (-37.09%)	⬇️
macrosynergy/panel/view_metrics.py	35.00% <100.00%> (ø)
macrosynergy/panel/view_timelines.py	22.85% <100.00%> (ø)
macrosynergy/visuals/__init__.py	100.00% <100.00%> (ø)
macrosynergy/visuals/timelines.py	59.79% <ø> (ø)
macrosynergy/panel/view_grades.py	17.30% <0.00%> (ø)
macrosynergy/panel/view_ranges.py	40.74% <66.66%> (+29.62%)	⬆️
macrosynergy/visuals/metrics.py	57.57% <42.85%> (ø)
macrosynergy/visuals/heatmap.py	83.48% <92.30%> (+10.75%)	⬆️
macrosynergy/management/check_availability.py	46.15% <14.28%> (+8.34%)	⬆️
... and 4 more

... and 2 files with indirect coverage changes