Pas transposition process

[daniel-montalvo]

This generates a new page within the guide to go through the steps involved in the PAS transposition process. This is mostly based on previously existing materials on the public guide as well
as on the Hitchhiker's guide.

[tidoust]

Thanks, @daniel-montalvo! I think it would be good to move or integrate the Selection Process page in the Guidebook afterwards as it currently still sits in a member-only page, but that can be done later on.

[daniel-montalvo]

Thanks, @daniel-montalvo! I think it would be good to move or integrate the Selection Process page in the Guidebook afterwards as it currently still sits in a member-only page, but that can be done later on.

Thanks @tidoust

I've just tried to incorporate here the bits I considered relevant but it seems reasonable to include the page for historical purposes. I can take this on on a different PR.