Improve ability to self-serve Snowplow SaaS Data for Product Managers

We have a page [Data for Product Managers](https://about.gitlab.com/handbook/business-ops/data-team/programs/data-for-product-managers/#sts=Usage%20Ping%20(Version%20App) that is helpful for product managers to understand the data and some of the tools that are available in GitLab. However, to get started to self-serve, update the SnowPlow data for GitLab SaaS is still relatively difficult.

I'd like to improve the handbook with better instructions, create simple tools in Sisense to enable product managers to self serve SnowPlow data for GitLab SaaS. This issue will capture all of the improvements.

• Template to create issues for SnowPlow instrumentation - MR
• Add Handbook instructions MR
• Create a SQL snippet for creating SnowPlow event charts