Document steps for updating the timeout parameters. (#8217)

closes: #8182 

This pull request adds documentation to the `UPGRADING.md` file as well as a set of deprecation checks for the old timeout parameters in the `config.toml` file. It additionally documents the parameters in the `genesis.md`.

cmd/tendermint/commands/root.go

@@ -51,10 +51,12 @@ func RootCommand(conf *config.Config, logger log.Logger) *cobra.Command {
 			}
 			*conf = *pconf
 			config.EnsureRoot(conf.RootDir)
-
 			if err := log.OverrideWithNewLogger(logger, conf.LogFormat, conf.LogLevel); err != nil {
 				return err
 			}
+			if warning := pconf.DeprecatedFieldWarning(); warning != nil {
+				logger.Info("WARNING", "deprecated field warning", warning)
+			}
 
 			return nil
 		},