Add discord role mentions for error notifications

What problem will this feature address?

Currently, when Discord webhook notifications are sent for errors (build failures, server threshold alerts, etc.), they are posted as regular messages without the ability to mention specific roles or users. This means that critical error notifications might be missed by the relevant team members who need to respond quickly to incidents.

In production environments, it's crucial that error notifications immediately alert the right people (DevOps team, on-call engineers, etc.) by mentioning their Discord roles, ensuring they receive proper notifications even when they're not actively monitoring the channel.

Describe the solution you'd like

Add a new optional field to Discord notification configuration called "Error Role Mentions" that allows users to specify Discord role IDs that should be mentioned when error-type notifications are sent.

The implementation should include:
- Add a new input field in the Discord notification form (in the dashboard settings)
- Allow users to enter multiple Discord role IDs (format: <@&123456789> or just 123456789)
- Include helpful text explaining how to get Discord role IDs
- Only show role mentions for error-type notifications (build errors, server threshold alerts, etc.)

Describe alternatives you've considered

1. Integration with Discord bot instead of webhooks: This would require more complex setup and authentication, while webhooks are simpler and already implemented.

2. Separate notification channels for errors: While possible, this adds complexity and many teams prefer to have all notifications in one channel with appropriate mentions for urgent issues.

Additional context

Discord role mentions work by including <@&ROLE_ID> in the message content. The role ID can be obtained by:

1. Enabling developer mode in Discord
2. Right-clicking on the role and selecting "Copy ID"

Example of how the notification would look:

<@&123456789> <@&987654321>
[Embed with error details]

This feature would significantly improve incident response times by ensuring the right people are immediately notified of critical issues

Will you send a PR to implement it?

Maybe, need help

Start by locating the Discord notification configuration form in the dashboard settings and the webhook path that sends error notifications. Trace how notification types are identified and how configuration is stored, then verify that configured role IDs appear only on error messages and that the form explains how to obtain them.