Add correct IP sorting for the ARP table

[DL6ER]

By submitting this pull request, I confirm the following:

• I have read and understood the contributors guide, as well as this entire template.
• I have made only one major change in my proposed changes.
• I have commented my proposed changes within the code.
• I have tested my proposed changes.
• I am willing to help maintain this change if there are issues with it later.
• I give this submission freely and claim no ownership.
• It is compatible with the EUPL 1.2 license
• I have squashed any insignificant commits. (git rebase)
• I have Signed Off all commits. (git commit --signoff)

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What does this PR aim to accomplish?:

1. Fix Network overview page is not correctly sorting for IP #947
2. Fix a bug causing the table to error if the name or macVendor fields are NULL.
   Note that this bug should never be triggered. We always inject (possibly empty) strings. However, manual interaction of the users with the database could trigger this as the columns are not explicitly marked NOT NULL.

How does this PR accomplish the above?:

1. Add ip-address type for DataTables columns
2. Check name and macVendor fields against being null before trying to access their .length property

[AzureMarker]

The codefactor issue has been ignored, but is not reflecting in the check.

Edit: there it goes

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/pi-hole-4-3-2-release-notes/23852/1