SDR bootcamp

Lets document the sdr onboarding content and tests for new hires like we do for sales. We can take content from the sales onboarding but now need to include all the stuff from TOPO on the playbook. Let's itemize out all the stuff they need to learn and then test their retention on it by having them submit issue within their glu project they set up.

Let's create a link from https://about.gitlab.com/handbook/sales/sdr/ to the content and tests.

/cc @francisaquino so he can help offer ideas