#8725-R: define UseRenderingOptimization

Redefine RenderingPrintComposition to UseRenderingOptimization
#8725-R: show map2pixel threshold in panels
#8725-R: simplifier execute in rendering loop
#8725-R: define QgsSimplifyMethod

Define QgsSimplifyMethod to use as optional parameter in
QgsFeatureRequest
#8725-R: VectorLayer use SimplifyMethod

VectorLayer define QgsVectorSimplifyMethod to configure the new
QgsSimplifyMethod member of QgsFeatureRequest
#8725-R: FeatureIterator use SimplifyMethod

AbstractFeatureIterator use SimplifyMethod to simplify locally the
geometries fetched from data source (provider)
#8725-R: move VectorSimplifyMethod to other file
#8725-R: FeatureIterator and other minor changes
#8725-R: OgrProvider simplifies on provider side

OgrFeatureIterator implements simplification on provider side
#8725-R: PostgresProvider simplifies on provider side

PostgresFeatureIterator implements simplification on provider side
#8725-R: New vector provider capability for topological simplification
#8725-R: no simplify point layers in postgres provider
#8725-R: never simplifying the first two or last two vertices in a line

This ensure that the angles at the line start and end are the same after
simplification