fix discovery, add metrics to receiver

3d_party/mongoose/install.sh

3d_party/mongoose/mongoose.c

3d_party/mongoose/mongoose.h

discovery/src/asapo_discovery/server/server.go

discovery/src/asapo_discovery/server/server_nottested.go

receiver/CMakeLists.txt

receiver/src/main.cpp

receiver/src/metrics/receiver_metrics_provider.h

receiver/src/metrics/receiver_metrics_server.h

receiver/src/metrics/receiver_mongoose_server.cpp

receiver/src/metrics/receiver_mongoose_server.h

receiver/src/metrics/receiver_prometheus_metrics.cpp

receiver/src/metrics/receiver_prometheus_metrics.h