Homogeneize wizard with other clients

Some changes are needed to follow what we have in all clients:

1. Update strings for welcome page

2. Add SIP account Create only when validated: cf

3. Update strings

4. Create a jami account should be divided in 4 steps: a. Choose username b. Encrypt with password c. Profile page (in background: generate the keys, it can be async) d. Backup page => nothing to do, just keep the one we have today

changed milestone to %Itération 21

added 1 deleted label

assigned to @abandali and unassigned @sblin

changed title from Copy wizard from client-qt to Homogeneize wizard with other clients

mentioned in issue #1199 (closed)

changed the description

mentioned in issue #1201 (closed)

mentioned in commit c8d1a872

mentioned in commit fedab0fa

mentioned in commit 7057c164

Done in the above commits.

closed

added ui/ux label