/cc @aardgoose

Discard attribute typed arrays for buffered geometries that are not modified after initial rendering (#9512)

* add setDiscardBuffer method to BufferGeometry

* added discard support to BufferAttribute

* add mechanism for discard of BufferAttribute TypedArrays

* use more elegant method for creating dummy typed array.

* fix typo

* Update BufferGeometry.js

fix brain fade

* rework to use callbacks (phase 1)

* rework part 2

* remove build file

* support setting onUploadCallback from Geometry

* remove repeated calculation from renderer

* remove now redundant getter

* remove geoemtry interface

* document discard mechanism.

* merge fixes

* restore return.this

* drop unneeded call()

* rename discard() method to disposeArray()

* save typed array info in attribute properties

* use saved attribute properties

* remove unused variable

* provide a means of copying the full buffer instead of just sub ranges

* use new API with setArray and needsFullBuffer

* rebuild full buffer contents when version is zero, set version to zero when array changes

* remove fullBuffer parameter from interleaved attrib

* revert comment to original

* revert earlier changes and just stick to bufferData for all non dynamic geometry

* remove spacing to clean up PR

* move is* properties to prototypes and remove unused ones

* rebuild

* merge dev -> less-is

* remove rebuild from PR

* convert to ES modules

* rebuild

* move shaders back into glsl files

* reinstate polyfills

This one uses a double hash, though the second hash is just a list that is linearly scanned as it is expected to be very small (there are not many edges per vertex).

Removed IndexBufferAttribute. Promoted index attribute to BufferGeometry. Maybe .addIndices() instead?
/ping @benaadams

/ping @benaadams