Adopt devfile format for workspaces configuration

[slemeur]

Description

Devfile is becoming the new way to define a workspace and we need to adopt its format for the workspaces.

User Stories

• In the dashboard, when the user is editing the definition of his workspaces, it must be based on the devfile format. issue
• In the dashboard, a user should be able to create a workspace by providing a devfile issue
• In the dashboard, a user should be able to export a workspace to a devfile.

(In other words, whereever we are displaying the workspace.json configuration in the dashboard, it should be replaced by devfile)

• [POC] Devfile format for Stack, Factory, Workspace API | [POC] Devfile format for Stack, Factory, Workspace API #13018
• Provide database layer storage and integrity of devfile as part of workspace | Provide database layer storage and integrity of devfile as part of workspace #13075
• [UD] Allow user to manage workspace devfile [UD] Allow user to manage workspace devfile #13067
• [UD] Workspace creation from devfile [UD] Workspace creation from devfile #13058
• Add an ability to use Devfile as workspace configuration as alternative to WorkspaceConfig Add an ability to use Devfile as workspace configuration as alternative to WorkspaceConfig #13079
• Make Theia respect Devfile of a field of Workspace Make Theia respect Devfile of a field of Workspace #13112

[skabashnyuk]

@slemeur all issues are done. can we close this epic?