MSSQL: Add connection timeout setting in configuration page (#58631)

* MSSQL add connection timeout

* add docs

* Update docs and add min value to the timeout setting

pkg/tsdb/sqleng/sql_engine.go

@@ -54,6 +54,7 @@ type JsonData struct {
 	MaxOpenConns        int    `json:"maxOpenConns"`
 	MaxIdleConns        int    `json:"maxIdleConns"`
 	ConnMaxLifetime     int    `json:"connMaxLifetime"`
+	ConnectionTimeout   int    `json:"connectionTimeout"`
 	Timescaledb         bool   `json:"timescaledb"`
 	Mode                string `json:"sslmode"`
 	ConfigurationMethod string `json:"tlsConfigurationMethod"`