add readme for implementation and update .gitignore

.gitignore

@@ -11,3 +11,7 @@ CTestTestfile.cmake
 _deps
 node_modules
 .vscode
+*/build/*
+EtsiServerGen/*
+!*/CMakeLists.txt
+!*/.openapi-generator-ignore

EtsiServerImpl/README.md

+# WORLD STORAGE CPP SERVER (PISTACHE)
+
+## Description
+
+This folder contains the source files for a basic implementation of the library you just created
+
+## Requirements
+
+- Boost
+- Pistache
+- a cpp compiler
+
+## Code usage
+
+Once you are in this directory, to build and execute the server, use the following commands:
+
+    mkdir -p build
+    cd build
+    cmake ..
+    make
+    ./HackPistacheServ
+