[IMP] l10n_SA: major update of the page following template

[afma-odoo]

task-4499493

[robodoo]

[afma-odoo]

Hi Ismail and @ygu-odoo , Thank you for your work on this Saudi-Arabia localization page! I made some changes/suggestions. Please take a look at it and let me know if you have any questions or comments. Thanks!

• Modules: All Saudi Arabia modules have been added.
• Structure: I reviewed the document to simplify the structure and align it with our new guidelines and templates for LOC documentation pages. Some sections were moved and added as notes/important alert blocks.
• Sandbox and simulation (line 272 & 273): It would be helpful to include more information about when to use one or the other. Could you provide it? 
• Simulation & Production (313): I split this section into two to be as precise and complete as possible: one for simulation modeand one for production mode.
• Re-onboard vs Onboard (298, 331 & 362): When I tested it (for the first time), the available option was "onboard". Is this okay?
• Invoice testing step (306 & 339), I added a step because a blue banner appears when I test it. Is this okay? Is this option also available in production mode?
• Invoice testing step (306 & 339), I added some information to make the instructions as precise as possible. Let me know if it's incorrect.
• QR code verification (453): I think we should add some more information about this note. What do you think?

Thank you for your help! ☺️