Improve Webinar Template

I have updated the webinar planning template to cover off the tasks I did to bring the last webinar together. We need to standardise as there is a lot to do for each one. I think this will help a lot.

Please review and provide feedback on anything I have missed etc.

I've done a first pass at tweaking wording (with suggestions of mostly as it didn't change meaning) and added various comments/suggestions. Back to Paul :) I'm happy to do a final pass at the end if it makes sense.

Update for findability