- Change `GOFMT` tool from `gofmt` to `gofumpt`
- Remove DockerHub deployment configurations
- Add detection and setup for Go environment variables
- Add conditional flags and executable naming based on OS
- Update `fmt` and `fmt-check` targets to use `gofumpt`
- Remove `lint`, `misspell-check`, and `misspell` targets
- Update `test` target to remove dependency on `fmt-check`
- Change `install` and `build` targets to use `GOFILES` instead of `SOURCES`
- Update `$(EXECUTABLE)` target to output to `bin/`
- Remove various `release` and `docker` related targets
Signed-off-by: appleboy <appleboy.tw@gmail.com>