fix/sentry: middlewares and span creation method (#54) Since discussions we had, I suggest the following change: - Merge ginsentry into sentryx (because of possible confusion with the legacy sentrygin package) - Rename Middleware to GinMiddleware (because of the package change) - Remove Recover since now it's embeded in the middleware - Catch panic in GinMiddleware, send it to Sentry and repanic. - Prefix URL params with `params` - StartSpan ensures the context used is not `gin.Context`. - Prefix params transaction tags with `param.`