Adds Title to Prefix Utilization to create Tooltip

[jvanderaa]

Fixes: #4611

Adds a multi-line tooltip to include:

• Addresses Used count

• Total available addresses

• Modifies the return of the get_utilization function to include the count used, and total available calculated

• Updates the utilization utility function to pass these values into the template

• Update the template to include a title to create a tooltip

[candlerb]

The image shows "Used: 24, Available: 254", and I think that's ambiguous: it could imply that 254 more addresses are available for allocation.

I suggest "Used: 24, Total: 254", or simply "Used: 24 / 254"

EDIT: I see the actual patch says "Used: ... Total Count: ..." which is fine.

[jvanderaa]

@jeremystretch @DanSheps this should be all set to go and is ready for merging.

[jeremystretch]

@jvanderaa while I appreciate the work you've put into this, I can't accept the level of complexity that has been introduced merely to display a count of IP addresses. There also remain some questionable choices, such as using namedtuple where it's not needed and accessing elements by numeric index within a template.

It would probably make more sense to introduce a separate table column to convey this information, rather than trying to inject it into the utilization graph. That would avoid the need to intermingle logic and rendering with the utilization graph.

[jvanderaa]

Agreed on the numeric index on the template. Seeing that, it is definitely a mistake there. I will get the update in that is this:

                    <td>Space Utilization</td>
                    <td>{% utilization_graph object.get_utilization %}</td>
                </tr>
                <tr>
                    <td>Power Utilization</td>
                    <td>{% utilization_graph object.get_power_utilization %}</td>

[jeremystretch]

@jvanderaa the much larger issue is the overall complexity being introduced: it's just trying to do too much at once. As I said, I'm not able to accept this PR, however I sincerely appreciate the effort.

Are you interested in pursuing an alternative approach using a separate table column? If so, I'll leave #4611 assigned to you. I'm afraid we have to close out this PR though.