refactor: http interfaces (#114)

* implement custom http handler interface

* implement trace_id

* normalize http method spacing for consistent logs

* fix failing test

* fix linter errors

* cleanup old dead code

* more route cleanup

* cleanup some inconsistent errors

* update and generate code

* make taskfile more consistent

* update task calls

* run tidy

* drop `@` tag for version

* use relative paths

* tidy

* fix auto-setting variables

* update build paths

* add contributing guide

* tidy

backend/pkgs/server/errors.go

@@ -0,0 +1,23 @@
+package server
+
+import "errors"
+
+type shutdownError struct {
+	message string
+}
+
+func (e *shutdownError) Error() string {
+	return e.message
+}
+
+// ShutdownError returns an error that indicates that the server has lost
+// integrity and should be shut down.
+func ShutdownError(message string) error {
+	return &shutdownError{message}
+}
+
+// IsShutdownError returns true if the error is a shutdown error.
+func IsShutdownError(err error) bool {
+	var e *shutdownError
+	return errors.As(err, &e)
+}