Batch renderer types

[ivanpopelyshev]

Can't build pixi-projection without it.

Those fields have to be overriden in constructor, cant do that in case of read-only.

Protected _shader is needed for extra renderer hacks.

Factory doesn't return BatchRenderer, it returns class of BatchRenderer.

[codecov-io]

Codecov Report

Merging #5871 into dev will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##              dev    #5871      +/-   ##
==========================================
+ Coverage   70.52%   70.53%   +<.01%     
==========================================
  Files         206      206              
  Lines       10407    10407              
==========================================
+ Hits         7340     7341       +1     
+ Misses       3067     3066       -1

Impacted Files	Coverage Δ
packages/core/src/batch/BatchRenderer.js	30.72% <ø> (ø)	⬆️
packages/core/src/batch/BatchPluginFactory.js	84.61% <ø> (ø)	⬆️
packages/ticker/src/Ticker.js	88% <0%> (+0.79%)	⬆️

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