[ENHANCE] Support label-based filtering for multi-tenant environments

[aslafy-z]

Is your feature request related to a problem? Please describe.
Forecastle currently supports grouping applications, but each app can only belong to a single group. In a multi-tenant Kubernetes setup, this limitation makes it difficult to dynamically filter and display only relevant applications per tenant.

For example, in a scenario where a reverse proxy injects a header with tenant-specific filtering criteria, there is no way to filter applications dynamically without either:

• Breaking the grouping functionality by filtering on groups.
• Running multiple Forecastle instances, which is inefficient for a dashboard.

Describe the solution you'd like
A label-based filtering mechanism where applications can have multiple labels (e.g., role=admin, role=viewer), and Forecastle could filter displayed applications based on injected request headers (e.g., X-Forecastle-Filter: role=viewer).

This would allow:

• More flexible multi-tenancy without affecting the grouping feature.
• Dynamic filtering via a reverse proxy injecting headers.
• Reduced overhead compared to running multiple Forecastle instances.

Describe alternatives you've considered

1. Filtering on groups - Possible, but it breaks the grouping functionality since an app can only belong to one group.
2. Running multiple Forecastle instances - Works but is inefficient, increasing resource consumption for a lightweight dashboard.

Additional context
This feature would enhance Forecastle’s usability in multi-tenant environments where different users need to see different subsets of applications dynamically. Would love to discuss implementation ideas and contribute if there’s interest!

[rasheedamir]

@waseem-h do you think we can handle this feature in the mega rewrite?