[Grant] jnxd - Sketcher refactor 2

[yorikvanhavre]

Second round of refactoring of the sketcher, by @AjinkyaDahale for 4000 EUR in two instalments.

Proposal: FreeCAD/FPA-grant-proposals#23

FPA approval: https://forum.freecad.org/viewtopic.php?t=95614

[yorikvanhavre]

Paid today 2000 EUR + 15 EUR transfer fee to @AjinkyaDahale for invoice 2025.04.Ajinkya, as installment 01 of 02, via BNP transfer. Reverse-charged VAT to by paid by the FPA = 2000 x 0.21 = 420 EUR