Information about SQLite limitations (#64990)

* Update _index.md

I am creating this PR to add more content about the SQLite (the default database for Grafana) limitations. SQLite is fine for small environments but not suitable when monitoring many Dashboards and sending lots of alerts frequently.

For e.g. this issue is just from this week and then got followed up by 3-4 more similar issues (all related to SQLite and are linked with this issue)

Closes #64664 

By adding more information, will have less frequency of such issues reported by users.

Also, once this PR get submitted, will also create a new PR about the possible workaround to not get the error message "database locked" while using SQLite.

* Update docs/sources/setup-grafana/installation/_index.md

Thank you. Also, can you please add this link to the High Availablity text as hyperlink.

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

* Update docs/sources/setup-grafana/installation/_index.md

* Update docs/sources/setup-grafana/installation/_index.md

---------

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

docs/sources/setup-grafana/installation/_index.md

@@ -54,6 +54,8 @@ Grafana supports the following databases:
 
 By default, Grafana installs with and uses SQLite, which is an embedded database stored in the Grafana installation location.
 
+> **Note:** SQLite works well if your environment is small, but is not recommended when your environment starts growing. For more information about the limitations of SQLite, refer to [Appropriate Uses For SQLite](https://www.sqlite.org/whentouse.html). If you want high availability, you must use a MySQL or PostgreSQL database. For information about how to define the database configuration parameters inside the `grafana.ini` file, refer to [[database]](https://grafana.com/docs/grafana/latest/setup-grafana/configure-grafana/#database).
+
 Grafana will support the versions of these databases that are officially supported by the project at the time of a Grafana version's release. When a version becomes unsupported, Grafana may also drop support for that version. See the links above for the support policies for each project.
 
 > **Note:** PostgreSQL versions 10.9, 11.4, and 12-beta2 are affected by a bug (tracked by the PostgreSQL project as [bug #15865](https://www.postgresql.org/message-id/flat/15865-17940eacc8f8b081%40postgresql.org)) which prevents those versions from being used with Grafana. The bug has been fixed in more recent versions of PostgreSQL.