Review and correct the readme and wiki to align with latest changes and logo

[Adam-it]

Some screenshots still have old look (logo) of the product. Also the technical wiki page with pipeline info is outdated.

Lets review:

• [x] readme
• [x] wiki
  • [x] home
  • [x] get started
  • [x] marketing resources
  • [x] technical reference
  • [x] welcome experience
  • [x] validate and set up a local workspace
  • [x] scaffolding
  • [x] login to tenant and retrieve ..
  • [x] gulp tasks
  • [x] actions
  • [x] teams toolkit integration
  • [x] help and feedback section
  • [x] coding snippets
  • [x] commands

and align it with the latest work done

[Adam-it]

done