Feature/organizations auth secret code

[SuperMuel]

Previously, all workspaces were visible to all users. Here we implement a simple Organizations and Authentication feature with Secret Code.

• Administrators can create Organisations in the database.
• Each Organisation has a name and a secret code.
• Each workspace is linked to an organisation.
• Only users knowing the organisation’s secret code can access the workspaces linked to the organization.
• The frontend’s landing page show a text input for the secret code. When users enter the secret code for an organization, they can use the app.
• Each secret code is unique. (No 2 workspaces with the same secret code)

**Warning : This is highly insecure and should not be used to protect confidential data : **

• Secret Codes are stored in plain text in both DB and maybe the browser
• The front exchanges the secret code against the organization's ID. We wrongly assume that the org ID can't be guessed, and dangerously use it for authentication.

Once the frontend obtained the Organization ID, it must provide a X-Organization-ID header in each request which is verified in the backend before returning resources.