Update to ArchiMate 3.2 specifications and reorganize folders to assist plantuml build

[jeanmarc]

Here's a PR to update ArchiMate-PlantUML with the files that have also been incorporated in plantuml/plantuml-stdlib and plantuml/plantuml. That way, this repo can continue to act as the source-of-truth for the ArchiMate stdlib.

The PR includes:

• Use half-arrowhead for association relationship (fixes Support association using half-arrowhead #53)
• Better align with the ArchiMate 3.2 specification (colors and shapes)
• use ortho lines by default (allows override via !global $ARCH_LINETYPE = curve or polyline)
• reorganize folders to simplify the transfers to plantuml/plantuml (embedded sprites) and plantuml/plantuml-stdlib (Archimate.puml and themes)
• Updates to readme and images to reflect latest look-and-feel and macros (fixes Readme shows example of macro that does not exist #55)

The files that are needed in the plantuml builds are located in ./dist, with the supporting files that are used to produce the SVG sprites in ./src/resources/ and ./scripts/. See ./src/resources/README.md for more information on generating the SVG sprites.

[jeanmarc]

@Potherca / @ebbypeter / @michiel (your handles have been linked to ArchiMate-PlantUML in the past), I hope you are OK with my proposed updates. I'd be happy to join the plantuml-stdlib organization to work as co-maintainer of the ArchiMate-PlantUML repo.
(my next contribution will be to reinstate alternative shapes for some elements like Motivation_Value, Motivation_Meaning, Technology_Node, in a way that can be activated easily)

[jeanmarc]

Set the PR to draft, as I will be adding updated images to reflect the latest definitions.