update scale 21x schedule.

[irabinovitch]

The schedule part of SCALE is super painful. We dont need this updated yet, but we will need to do it closer to Nov / December when we know what the schedule is.

The steps for this that I'm aware of are:

• create a panel for Schedule 21x (https://www.socallinuxexpo.org/admin/structure/panels)
• edit the selection criteria for each of thur, fri, sat, sun to have the correct date range and room list.

You can look at the 20x version for examples:
https://www.socallinuxexpo.org/admin/structure/pages/edit/page-schedule_20x

@btmash or @DrupalPhil can hopefully point us to how to do this in CODE rather than in the drupal UI as content.