Use HTTP interface for parametric tests

[cbeauchesne]

trafficstars

• [x] C++ #1942 ❤️ @dmehala
• [ ] golang
• [x] .NET #2108
• [x] java #2869
• [x] NodeJs #1900 ❤️ @ZStriker19
• [x] PHP first HTTP interface
• [x] Python #1929 #1959
• [ ] Ruby

Then:

• [ ] remove every legacy GRPC code in parametric tests