Add vcpkg manifest

vcpkg.json

+{
+  "name": "caosdb",
+  "version-string": "0.3.0-dev",
+  "port-version": 1,
+  "description": "C++ library for the CaosDB project",
+  "dependencies": [
+    "grpc",
+    "protobuf",
+    "boost-log",    
+    "boost-filesystem",
+    "boost-smart-ptr",
+    "boost-beast",
+    "boost-json",
+    "boost-thread",
+    "zlib"
+  ],
+  "license":"AGPL-3.0-or-later"
+}