Renderer protocol

[jjatie]

Renderer and DataRenderer are now protocols instead of classes.

[jjatie]

@liuxuan30 @petester42 @danielgindi There are changes here that pave the way to much larger changes to the framework which allow better type safety and less reliance on optionals. This is immediately followed by #2990. Once these two are approved, there will be more changes that can be quickly and easily made to greater improve the type safety and the use of optionals across the entire framework.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (4.0.0@df62114). Click here to learn what that means.
The diff coverage is 18.91%.

@@           Coverage Diff            @@
##             4.0.0    #2991   +/-   ##
========================================
  Coverage         ?   20.58%           
========================================
  Files            ?      112           
  Lines            ?    15431           
  Branches         ?      256           
========================================
  Hits             ?     3176           
  Misses           ?    12218           
  Partials         ?       37

Impacted Files	Coverage Δ
Source/Charts/Utils/ViewPortHandler.swift	28.18% <ø> (ø)
...ource/Charts/Renderers/CombinedChartRenderer.swift	0% <0%> (ø)
Source/Charts/Renderers/BubbleChartRenderer.swift	0% <0%> (ø)
Source/Charts/Renderers/PieChartRenderer.swift	0% <0%> (ø)
...ts/Renderers/YAxisRendererHorizontalBarChart.swift	0% <0%> (ø)
Source/Charts/Renderers/LegendRenderer.swift	41.52% <100%> (ø)
Source/Charts/Renderers/AxisRendererBase.swift	58.18% <100%> (ø)
...Renderers/BarLineScatterCandleBubbleRenderer.swift	46% <26.31%> (ø)

---

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[jjatie]

This includes #2980

[jjatie]

@liuxuan30 After #2982 I think this one should be done next

[liuxuan30]

oops just read your comment.
I would suggest you create an issue to track your PRs, like which are for 4.0 branch and which can be merged into master directly. I feel dizzy switching around the PRs not sure which to start with. Some "minor" changes have hundreds of diffs, which are not minor to review.

I would first start with diffs that are just two digits and later with the big ones.

[jjatie]

I'll just change the destination branch on the PR to 4.0.0.

Also, I will start making more PRs into 4.0.0. I think some of my changes are big enough to warrant 4.0.0 even if they're not breaking.

[jjatie]

In the future I will create Issues and name the PRs after them.

[jjatie]

Continued in #3136