[VAD] Update agents RDV wizard to choose a location

Created by: adipasquale

https://trello.com/c/SbLo91uF/594-vad-pose-dun-rdv-sur-lagenda

ℹ️ this PR can be read commit by commit, they are pretty self-contained ℹ️ Screenshots below 👇

Updates in the RDV Wizard:

• Reorder the steps : you now choose users before choosing the date, location and agents
• Ask for a location for VAD rdvs. Defaults to the first user's address
• Display motifs 'options' (online / phone / VAD) in the dropdown and labels
• Slightly change the header row of already selected options during step 2
• explicited a few wordings :
  • "Choisir l'usager" -> "Choisir le ou les usagers"
  • "Créer" -> Créer un usager / Créer RDV

Updates in "Trouver un Creneau":

• Display motifs 'options' (online / phone / VAD) in the dropdown
• Redirect towards step 2 of the RDV wizard (pick users) instead of step 3

new steps ordering:

Step 1

Step 2

Step 3