[TF2] add BLU disguise kit

[condor00fr]

The disguise kit has an unused BLU variant that we can see it in meet the spy. The red button is colored blu and the cigarrets are brown instead of white wich matches the Blu spy's texture:

If you look closely you can see it.

[Ismaciodismorphus]

[ShadowMan44]

Huh, never knew this! Yeah that'd be pretty sweet for them to finally add more unused team color variants.

[condor00fr]

Yes, lots of weapons would need team coloring like the winger or the razorback, however it's not much known if official textues of theses ever existed. I bet they do.

However the stock bottles were going to team colored at some point with a different RED texture and a unused BLU one that would maches the current design one we have today. And guess what. We found them in the postal leak!
The BLU variant would be cool to see in game as well.

[ShadowMan44]

Documented this on the TF2 Wiki (if that helps).

[BreavyTF2]

Replying to #4301 (comment)

We actually do have the texture, thanks to maxofs2d backing up the sfm beta files.

[condor00fr]

Documented This on the French version of the wiki. Thanks Shadowman44 for the idea.

[ShadowMan44]

Now would be a really good time to add this.