Adding Query Performance Investigation Template

.gitlab/issue_templates/Query Performance Investigation.md

+## Description
+
+As the name implies, the purpose of the template is to detail underperforming queries for futher investigation.
+
+### Steps
+
+- [ ] Rename the issue to - `Query Performance Investigation - [Query Snippet | Table info]`
+  - For example - `Query Performance Investigation - SELECT "namespaces".* FROM "namespaces" WHERE "namespaces"."id" = $1 LIMIT $2`
+- [ ] Provide information in the Requested Data Points table
+- [ ] Provide [priority and severity labels](https://about.gitlab.com/handbook/engineering/quality/issue-triage/#availability)
+- [ ] If this requires immediate attention cc `@gitlab-org/database-team` and reach out in the #g_database slack channel
+
+### Requested Data points
+
+Please provide as many of these fields as possible when submitting a query performance report.
+
+- TPS
+- Duration
+- Source of calls (Sidekiq, WebAPI, etc)
+- Query ID
+- SQL Statement
+- Query Plan
+- Query Example
+- Total number of calls (relative)
+- % of Total time
+
+<!--
+
+- Example of a postgres checkup report - https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/snippets/2056787
+- Epic - Improving the Database resource usage (&365) - https://gitlab.com/groups/gitlab-com/gl-infra/-/epics/365#short-term-query-improvements
+- Past examples of query performance investigations that have led to this template creation. 
+ - Possible Index suggestion or query rewriting (#292454) - https://gitlab.com/gitlab-org/gitlab/-/issues/292454)
+ - High number of Sessions to the database with the value SET parameter (#292022) - https://gitlab.com/gitlab-org/gitlab/-/issues/292022)
+ - Query performance "Select 1" (#220055) - https://gitlab.com/gitlab-org/gitlab/-/issues/220055
+ - Select statements that are in execution during database CPU utilization peak times - licenses table (#292900)  - https://gitlab.com/gitlab-org/gitlab/-/issues/292900
+
+-->
+
+/label ~"group::database" ~"database::triage"