PHPCS for Class FTP files

[SirLouen]

Discussion coming from here: #63416

First things first, we need to confirm if it's time to remove PHPCS exclusions for PHPCS before moving forward in PHPCS formatting in the individual tickets (including the latest update [59846] that is actually updating PHPCS in one of the 3 FTP files).

I note this to raise in the next dev-chat and whatever decision, I will update here either continuing and committing, or dismissing (and maybe reverting [59846]

Time to open FTP Classes for PHPCS?
Nothing to test here.

Trac ticket: https://core.trac.wordpress.org/ticket/63436

[SirLouen]

The two main topics commented in the last <dev-chat>

1. @westonruter suggested adding PHPCS checks simply to new lines in PRs (to avoid the late increase of PHPCS number of tickets).
2. @joemcgill and @desrosj proposed doing a full audit of current external libs and see which are still maintained upstream before taking further steps in this regard.

We could use this topic for further discussion about this (considering that PemFTP is one of those abandoned libraries that will not receive upstream support anymore).

Since class-ftp is and will be maintained by WordPress developers for now and the future, it makes sense to open the PHPCS dam because PHPCS, as @desrosj pointed out in the meeting, brings more clarity to the code (and the main reason of the approval of [59846])

But we must assume that this will be on hold until some action taken (like acting on the proposed audit)