Complete code refactoring

- `LOGGING` environment variable `json` or `human`
- `NODEID` environment variable (integer)
- Much cleaner go code
- Listener for exit of program to do cleanup
- All code is in packages except main.go
- Custom logger package added
- Connectivity checks reworked
- Healthcheck server on localhost only, so not exposed to outside world
- Updated `go.mod` and `go.sum`

.gitignore

@@ -1,14 +1,2 @@
-# Binaries for programs and plugins
 *.exe
-*.exe~
-*.dll
-*.so
-*.dylib
-
-# Test binary, build with `go test -c`
-*.test
-
-# Output of the go coverage tool, specifically when used with LiteIDE
-*.out
-
 .vscode