Materials: cards, add concrete matrix and reinforcement materials

- safety factor is included in material params
- this is for sure not a material parameter
- but FreeCAD has no safety factor yet
- workaround: directly include them in the material parameter
- structural engineers have a lot of them in limeted state design

src/Mod/Material/StandardMaterial/Concrete-EN-C35_45.FCMat

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+; Concrete-EN-C35_45
+; (c) 2019 Bernd Hahnebach (CC-BY 3.0)
+; information about the content of such cards can be found on the wiki:
+; https://www.freecadweb.org/wiki/Material
+
+
+[General]
+Name = Concrete-EN-C35/45
+Description = Concrete matrix for reinforcement material examples, 0.6 x 0.75 x 35 MPa = 15.75 MPa (https://forum.freecadweb.org/viewtopic.php?f=18&t=33106&start=200#p311075)
+Father = Aggregate
+
+[Mechanical]
+AngleOfFriction = 30 deg
+CompressiveStrength = 15.75 MPa
+Density = 2500 kg/m^3
+PoissonRatio = 0.17
+YoungsModulus = 32000 MPa
+
+[Cost]
+ProductURL = https://en.wikipedia.org/wiki/Concrete

src/Mod/Material/StandardMaterial/Reinforcement-FIB-B500.FCMat

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+; Reinforcement-FIB-B500
+; (c) 2019 Bernd Hahnebach (CC-BY 3.0)
+; information about the content of such cards can be found on the wiki:
+; https://www.freecadweb.org/wiki/Material
+
+
+[General]
+Name = Reinforcement-Harry
+Description = Reinforcement inside concrete for reinforcement material examples, from fib examples, 0.84 x 0.75 x 500 MPa = 315 MPa (https://forum.freecadweb.org/viewtopic.php?f=18&t=33106&start=200#p311705)
+
+[Mechanical]
+Density = 7850 kg/m^3
+PoissonRatio = 0.3
+YieldStrength = 315 MPa
+YoungsModulus = 210000 MPa