[v9.5.x] SQL Datasources: Update Max Connection and Max Idle Connection Defaults to 100 and add auto mode (#66651)

* SQL Datasources: Update Max Connection and Max Idle Connection Defaults to 100 and add auto mode (#65834)

* Update connection configuration for SQL datasources

* Working auto state for connection numbers

* Add migration

* Use defaults from constants file

* Remove dead code

* Add tests and restructure useMigrateDatabaseField

* Update function names

* Update docs

* Make sure we don't continually issue updates

* Update docs

* Use onOptionsChnage in ConnectionLimits

* Update docs

* Clean up docs

* Update migration

* Fix default values in docs

* Fix spacing issue

* Fix test

* Update default values for SQL connections

* Include consts

* Allow override for default SQL datasource connection parameters

* Fix linter errors

* Remove extra @ts-ignore

* Centralize logic for default values

* Remove debugging

* Remove unecessary function

* Update configuration docs

* minor suggested change

* Fix comment misspelling

* Remove unecessary default setting code

* Update docs to indicate that code was included for backport version

* Remove dead code

---------

Co-authored-by: lwandz13 <larissa.wandzura@grafana.com>
(cherry picked from commit 92d92187d9)

* Add brackets around property name so that it's dynamic

---------

Co-authored-by: Kyle Cunningham <codeincarnate@users.noreply.github.com>
Co-authored-by: Kyle Cunningham <kyle@codeincarnate.com>

pkg/tsdb/sqleng/sql_engine.go

@@ -84,6 +84,13 @@ type DataSourceInfo struct {
 	DecryptedSecureJSONData map[string]string
 }
 
+// Defaults for the xorm connection pool
+type DefaultConnectionInfo struct {
+	MaxOpenConns    int
+	MaxIdleConns    int
+	ConnMaxLifetime int
+}
+
 type DataPluginConfiguration struct {
 	DriverName        string
 	DSInfo            DataSourceInfo