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