Using arc angles to plot an arc is really error prone due to different
options between plotters, and angles defined in Kicad, using this version of
arc plotting from Kicad is no longer allowed in Kicad code.
Also moves most navigation code to SCH_NAVIGATION_TOOL.
Also changes page number href to anchor syntax ('#foo').
Also adds hypertext processing to SCH_TEXTBOXes.
Also adds combobox with schematic pages to text properties dialog.
It avoid trying to calculate arc angles (start, end or arc angle) that
frequently create issues due to reverse Y axis, plot mirrored and/or
angle normalization with different criteria.
Fixes#10914https://gitlab.com/kicad/code/kicad/issues/10914
jean-pierre charras
Jeff Young
Mark Roszko
Wayne Stambaugh