feat(notifications): improve discord notifications

[guillaumearnx]

Description

Added a field in the general notification settings to allow a role to be mentioned in the webhook message via discord notification agent

Screenshot (if UI-related)

To-Dos

• [X] Successful build pnpm build
• [X] Translation keys pnpm i18n:extract
• [ ] Database migration (if required)

[gauthier-th]

Can you please rebase (not merge) on develop and generate translations one more time with pnpm i18n:extract?

[guillaumearnx]

Done. but pnpm i18n:extract didn't change content of en.json file