Added bulk reassignment of workspaces roles

[Max-7]

Closes #5938

1. Can only assign roles on workspaces where the client is Manager or Owner
2. When assigning to an Outsider, Manager and Owner roles are converted to Contributor
3. If the client is a Manager, and the role to assign is Manager or Owner, the role assigned becomes Contributor (a Manager cannot set roles higher than Contributor)
4. If the user has a higher role on the workspace than the one we want to assign, do nothing

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[FirelightFlagboy]

I validate the file misc/generate_pyqt.py

[mmmarcos]

Only some suggestions regarding the docs, otherwise LGTM 👍

Also, can you regenerate the images to replace the "Toto" user and its mail? It may seem like a detail, but it makes the docs look unprofessional

[mmmarcos]

A few more suggestions regarding the docs and screenshots.

Otherwise LGTM 👍

[mmmarcos]

The text was changed:

[mmmarcos]

The context menu item that opens this dialog is named "Assign workspace roles to another user".
However, once opened, it is not immediately clear what the dialog is about.

Even if that is explained in the following step, I think we can improve it a little bit:

• Title: Assign Bob workspace roles to: (with the username emphasized? 🤔)
• Description: Select a user to see the roles that will be assigned.

[mmmarcos]

I'd use "tedious" instead of "annoying":

Suggested change

	Assigning the same roles to multiple users on multiple workspaces can be a bit annoying. Parsec provides a way to bulk assign the roles of one user to another.
	Manually assigning the same workspace roles to multiple users can be a bit tedious and error prone. Parsec provides a way to bulk assign the roles from one user to another.

In French:

L'assignation manuelle des mêmes rôles d'espace de travail à plusieurs utilisateurs peut s'avérer fastidieuse et source d'erreurs. Parsec propose un moyen d'attribuer en bloc les rôles d'un utilisateur à un autre.

[mmmarcos]

Suggested change

	3. You're shown a summary of what roles are going to be assigned on each workspace. Click on `Assign roles` to complete the operation.
	3. You're shown a summary of which roles are going to be assigned on each workspace. Click on `Assign roles` to complete the operation.

[mmmarcos]

Suggested change

	1. You can only assign roles on workspaces where you are an Owner or Manager
	2. Outsider cannot have a role higher than Contributor
	3. You cannot assign roles higher than your own. If you have the Manager role in a workspace and you're trying to assign the Owner role, it will be downgraded to Contributor).
	1. You can only assign roles on a workspace where you have an Owner or Manager role
	2. An Outsider user cannot have a role higher than Contributor
	3. You cannot assign roles higher than your own. If you have the Manager role in a workspace and you're trying to assign the Owner role, it will be downgraded to Contributor.