Update Explainer_Training.md

[andrewjskatz]

Aligning with C-Suite explainers, and adding Implications and Benefits

[myagi2019]

For implications: add something about OSS specific training materials is required, which may vary by role, and needs to be tracked/recorded in some way?
For Solution: add something like training courses/materials is available from the Linux Foundation (name the 2 courses), the OC Education WG, solution & training suppliers or may be made internally