Related issue:
#5603
Previous PR:
#11010
* This PR implements the new PlaneGui class for the Draft_SelectPlane command.
* As mentioned in the previous PR, almost all working plane related code has been removed from gui_selectplane.py.
* The task panel has a new button "Next" to switch to the next working plane in the history.
* Both the "Previous" and "Next" buttons are only enabled if there is a corresponding step in the history.
* PlaneGui stores a working plane per 3D view, but the other commands have to be updated before that system is fully functional.
* Code to update the toolbar when switching to a different view will be added later.
Found via `codespell -q 3 -L aci,ake,aline,alle,alledges,alocation,als,ang,anid,apoints,ba,beginn,behaviour,bloaded,bottome,byteorder,calculater,cancelled,cancelling,cas,cascade,centimetre,childs,colour,colours,commen,connexion,currenty,dof,doubleclick,dum,eiter,elemente,ende,feld,finde,findf,freez,hist,iff,indicies,initialisation,initialise,initialised,initialises,initialisiert,ist,kilometre,lod,mantatory,methode,metres,millimetre,modell,nd,noe,normale,normaly,nto,numer,oder,ontop,orgin,orginx,orginy,ot,pard,parms,pres,programm,que,recurrance,rougly,seperator,serie,sinc,strack,substraction,te,thist,thru,tread,uint,unter,vertexes,wallthickness,whitespaces -S ./.git,*.po,*.ts,./ChangeLog.txt,./src/3rdParty,./src/Mod/Assembly/App/opendcm,./src/CXX,./src/zipios++,./src/Base/swig*,./src/Mod/Robot/App/kdl_cp,./src/Mod/Import/App/SCL,./src/WindowsInstaller,./src/Doc/FreeCAD.uml,./build/doc/SourceDocu`
Small spacing fixes like imports in separate lines
for more clarity, and the position of the license.
Added many docstrings to clarify the methods, and spaces
after commas in order to comply with Python PEP8 style.
Also break many lines so that they are shorter than 80 characters.
Also import `todo` and `translate` from the utils module
instead of from `DraftGui`.
Otherwise we have to import the entire `DraftGui` module
which creates dependency problems when we want to use
some functions without the graphical interface.
