Add material visualization for TileCal

This MR adds the materials used for Tile in rel.22 to gmexMatVisAttributes.json. With these additions, Tile geometry is visualized as in VP1¹.

Before the extra definitions:

After the extra definitions introduced with this MR, where 7 materials have been declared:

The newly defined materials are:

• std::Air
• std::Iron
• std::Aluminium
• tile::SiO2CondEpox
• tile::Glue
• tile::Scintillator
• LArServices

I left out the definition of LArIronBox because I didn't want to make it look like std::Iron. We can choose a color for it later.

---

Note:

At a later stage, we need to decouple the experiment-specific material names/definitions to additional files, which the user can specify when launching gmex.

[Probably, the files containing the ATLAS materials could be stored in the GeoModelATLAS or GeoModelDATA repositories. To be discussed]

---

Footnotes:

1. (Almost identical to VP1: I found, in fact, that in VP1 the scintillator is colored as greenish, while for the moment I only found a definition for a blueish "Scintillator" color; but, nevertheless, the material is visualized differently than the surrounding volumes, which is the important thing so far)

GeoModelVisualization/VP1GeometrySystems/share/gmexMatVisAttributes.json

@@ -49,7 +49,8 @@
                 "R": 0.0
             },
             "name": [
-                "Aluminium"
+                "Aluminium",
+                "std::Aluminium"
             ],
             "shininess": 0.23000000417232513,
             "specular": {
@@ -325,7 +326,8 @@
                 "R": 0.0
             },
             "name": [
-                "Epoxy"
+                "Epoxy",
+                "tile::SiO2CondEpox"
             ],
             "shininess": 0.7212120294570923,
             "specular": {
@@ -460,7 +462,8 @@
                 "R": 0.0
             },
             "name": [
-                "Iron"
+                "Iron",
+                "std::Iron"
             ],
             "shininess": 0.6000000238418579,
             "specular": {
@@ -714,6 +717,7 @@
             },
             "name": [
                 "MatGlue",
+                "tile::Glue",
 		"pix::GlueOmegaStave_BL0",
 		"pix::GlueOmegaStave_L10",
 		"pix::GlueOmegaStave_L20"
@@ -1155,7 +1159,8 @@
                 "R": 0.0
             },
             "name": [
-                "Scintillator"
+                "Scintillator",
+                "tile::Scontillator"
             ],
             "shininess": 0.9818180203437805,
             "specular": {
@@ -1182,7 +1187,8 @@
                 "R": 0.0
             },
             "name": [
-                "Services"
+                "Services",
+                "LArServices"
             ],
             "shininess": 0.20000000298023224,
             "specular": {