[proposal] Conventional code formatting style.

[tttoad]

I use gopls to format the code.

I habitually format files when I modify code, which creates many changes.
example:

opamp-go/server/serverimpl.go

Lines 22 to 32 in b7beae5

	var (
	errAlreadyStarted = errors.New("already started")
	)
	const defaultOpAMPPath = "/v1/opamp"
	const headerContentType = "Content-Type"
	const headerContentEncoding = "Content-Encoding"
	const headerAcceptEncoding = "Accept-Encoding"
	const contentEncodingGzip = "gzip"
	const contentTypeProtobuf = "application/x-protobuf"

Format to:

var errAlreadyStarted = errors.New("already started")

const (
	defaultOpAMPPath      = "/v1/opamp"
	headerContentType     = "Content-Type"
	headerContentEncoding = "Content-Encoding"
	headerAcceptEncoding  = "Accept-Encoding"
	contentEncodingGzip   = "gzip"
	contentTypeProtobuf   = "application/x-protobuf"
)