[TF2] [Feature Request] Change "mud", "gravel" and "glass"'s friction values to be normal

[Ashetf2]

Their values for "friction" are "0.6", "0.4" and "0.5", respectively, in HL2's surfaceproperties.txt, but this is weird, as those are used as map geometry and don't have a reason to be slippery (normal value is 0.8).

For example, in Metalworks, this spot is glass, and it is slippery, which is not good because Metalworks is highly played in Competitive.

https://user-images.githubusercontent.com/63692647/193615005-8aac5bfe-6344-49f3-b56a-4ec44844edaa.mp4

Gravel and mud:

https://user-images.githubusercontent.com/63692647/193618350-a503b584-7d1f-4eb5-b281-3b3dfd0140e7.mp4

I suggest to add mud, gravel and glass to "surfaceproperties_tf.txt" with normal friction values, for the sake of gameplay. For example:

"mud"
{
    "base"       "dirt"
//BEFORE        "friction"   "0.6"
    "friction"   "0.8"

    "dampening"  "6.0"

    "stepleft"   "Mud.StepLeft"
    "stepright"  "Mud.StepRight"

    "audiohardnessfactor" "0.0"
    "audioroughnessfactor" "0.1"
}

[Ashetf2]

I created a submission in Workshop! Instead of changing the friction values, I created new material types: "gravelfloor", "glassfloor" and "mudfloor" with normal friction values.

https://steamcommunity.com/sharedfiles/filedetails/?id=2956923051