Allow file:// links in the "Documents" field for contracts

[diegogodoy06]

NetBox Version: Community v4.3.1
Module: Contracts → Documents field (URL to the contract documents)

Hello NetBox team! 👋

I would like to propose a small but useful enhancement for the Contracts feature.

Currently, the "Documents" field only accepts links that begin with http:// or https://.

Proposal
Enable support for links using the file:// scheme, to allow referencing documents stored on local networks or internal file servers.

Example:
file://10.0.0.0/ti/exemple/Contrato.pdf

Why this matters
Many organizations (including mine) store contracts on internal file servers, often accessed via local network shares.

Allowing file:// links would:

Improve integration with existing document storage systems;
Avoid unnecessary duplication just to host documents over HTTP;
Enhance NetBox as a central source of reference for documentation and compliance.
Security Considerations
I understand that file:// links may have browser-related security implications. To address that, I suggest:

Making support for file:// links configurable via settings;
Or displaying a warning when such links are used, leaving the choice to the administrator.