fix(scan-network): block network scan for large network (/19 or lower)

[m-dilorenzi]

This pull request updates the network scanning functionality in the DNS/DHCP UI to restrict scans to interfaces with a /20 netmask or larger. It introduces new UI feedback to inform users when a network is too large to scan, updates the relevant props and interface definitions, and improves the scan button behavior. Additionally, it updates internationalization strings to reflect these changes.

Network scan restriction and UI feedback:

• The scan network button is now disabled for interfaces with a netmask smaller than /20, and a tooltip explains the restriction to the user.
• Added a new prop scanButtonDisabledNetworkTooLarge and updated the logic to control the scan button's disabled state and tooltip display.

Data and interface improvements:

• The ScanInterface type now includes a netmask property, and the interface list is populated with this data from the backend.

Scan request improvements:

• The scan request now sends both device and interface parameters to the backend for more precise operation. (ScanNetwork.vue)

Internationalization updates:

• Updated English and Italian descriptions to clarify the scan restriction, and added a new message for the tooltip explaining the limitation.

Refs: NethServer/nethsecurity#1434

[m-dilorenzi]

Using the ip -j address command in the backend lets you handle interfaces that aren’t statically configured (ex. DHCP, OpenVPN tunnels, etc.), for which the netmask can’t be retrieved via UCI because it isn’t explicitly configured there. The backend will send the information scan_available for all networks (no more the netmask value), allowing you to avoid the error (by disabling the scan button) on all types of networks.