[Doc] Add core processes

[roigcarlo]

📝 Description
First part of the core processes documentation.

Only the most critical processes are added to this PR. More on the way

@sunethwarna

🆕 Changelog

• Adding doc for assign processes.
• Adding template files for of the core processes.
• Adding processes structure to the doc.
• Update sequence diagrams of analysis stage.

[sunethwarna]

Thanks @roigcarlo

[roigcarlo]

Seems that for some reason doc is triggering compilation of the core again. I will look into it.

Edit. Puff... actions/runner#2324