Display active and total number of DHCP leases

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### Prerequisites

Please answer the following questions for yourself before submitting an issue. **YOU MAY DELETE THE PREREQUISITES SECTION.**

- [x] I am running the latest version [**v0.107.0-b.15**]
- [x] I checked the documentation and found no answer
- [x] I checked to make sure that this issue has not already been filed

### Problem Description
The number of active and total DHCP leases is not displayed

### Proposed Solution
Display the number of active DHCP leases and the number of total leases available from the given range.

### Alternatives Considered
None

### Additional Information

It would be nice to have a quick count of active DHCP leases and the total number of leases allocated by the given range. I had an issue where I miscounted and put a smaller range in than I required, leading to devices unable to obtain a DHCP lease. It took a bit of digging to figure out it was a DHCP shortage due to my math error. I figured it would be nice to have a small visual confirmation on the DHCP page for the number of active and total leases available.

Thanks for the consideration.