feat: added multi-select feature for tasks list

[Mastermind-sap]

Description

Implemented multi select feature for tasks list which enables us to complete or delete multiple tasks easily and also undo them at one go.

Fixes #467

Screenshots

Checklist

• [ ] Tests have been added or updated to cover the changes
• [ ] Documentation has been updated to reflect the changes
• [x] Code follows the established coding style guidelines
• [ ] All tests are passing

[Mastermind-sap]

@SGI-CAPP-AT2 rebased