Update YUI JavaScript library to YUI3

[amaltaro]

Impact of the new feature
T0, WMAgent and WorkQueue

Is your feature request related to a problem? Please describe.
As I investigate another problem with pushing couchapps, it turns out that the YUI javascript/css library that some of our DMWM services use has been deprecated since 2011 (!!!), see:
https://yui.github.io/yui2/

The recommended library is YUI3, and we seem to already have the spec and some COMP services depending on it. So we should update the other specs to the newest library as soon as possible.

Describe the solution you'd like
Update our WMCore-related spec files depending on yui to yui3. We should also profit from this opportunity and try to update the yui3 version, if possible.

Describe alternatives you've considered
This must be done for yesterday! But we better wait for the python3 services deployment first, to avoid having too many changes all in at the same time.

Additional context
Somehow related: #10596

[amaltaro]

This is not as simple as a library update. yui3 library provides a completely different library and it will require implementation changes on how we use it.

Most of the code under src/html/ can go away though, while special attention is required for src/couchapps

[todor-ivanov]

This issue introduces a very bad hold off of an obsolete library, which on the other hand was blocking this issue : #8797 from progressing.

This situation led to a really unpleasant hack implemented at: dmwm/CMSKubernetes#1364, which was basically - to manually download from cmsrpo and unpack at the destination, the obsolete yui 2.9 package.

What we need to do here is not only upgrade to a newer version of this package, but completely re-estimate the need of it and refactor the code if possible. Because yui v2.9 was announced deprecated on 2011 and since then it was pending on us to upgrade our spec files and start building rpms with the new version. But in the meantime even yui3 was announced as unsupported since 2014:
https://yahooeng.tumblr.com/post/96098168666/important-announcement-regarding-yui .

So currently we need to get rid of it completely if possible.

FYI: @amaltaro @vkuznet @khurtado

[vkuznet]

@todor-ivanov , could you please clarify where YUI library is used.