[MM-42167] Add configuration tables to migration system (#19671)

* add configuration tables to migration system

* config: move config migrations into new system completely

* add mysql specific bits

* use helper db instance instead

* fix typo

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

config/utils.go

@@ -10,6 +10,7 @@ import (
 	"reflect"
 	"strings"
 
+	"github.com/go-sql-driver/mysql"
 	"github.com/mattermost/mattermost-server/v6/model"
 	"github.com/mattermost/mattermost-server/v6/shared/i18n"
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
@@ -261,3 +262,29 @@ func equal(oldCfg, newCfg *model.Config) (bool, error) {
 	}
 	return !bytes.Equal(oldCfgBytes, newCfgBytes), nil
 }
+
+// appendMultipleStatementsFlag attached dsn parameters to MySQL dsn in order to make migrations work.
+func appendMultipleStatementsFlag(dataSource string) (string, error) {
+
+	config, err := mysql.ParseDSN(dataSource)
+	if err != nil {
+		return "", err
+	}
+
+	if config.Params == nil {
+		config.Params = map[string]string{}
+	}
+
+	config.Params["multiStatements"] = "true"
+	return config.FormatDSN(), nil
+}
+
+// resetReadTimeout removes the timeout contraint from the MySQL dsn.
+func resetReadTimeout(dataSource string) (string, error) {
+	config, err := mysql.ParseDSN(dataSource)
+	if err != nil {
+		return "", err
+	}
+	config.ReadTimeout = 0
+	return config.FormatDSN(), nil
+}