Focus order updates for record page

[mikejritter]

What does this do?

• Render the sidebar toggle button as part of the record sidebar
• Update css to keep sidebar styling consistent with previous behavior

Why are we doing this? (with JIRA link)
Jira: https://collectionspace.atlassian.net/browse/DRYD-1309

These are similar changes to those in #209 but for the record page. This makes the tab ordering logically consistent by having the sidebar toggle button be part of the record sidebar.

How should this be tested? Do these changes have associated tests?

• Run the devserver
• Create a new record (group is a good choice as it's small)
• Cycle through the focusable elements using tab
  • The expected order is to go through the record form, then then sidebar toggle, then the sidebar
• Toggle and untoggle the sidebar and see that the form fills to the width of the page

Dependencies for merging? Releasing to production?
None

Has the application documentation been updated for these changes?
No

Did someone actually run this code to verify it works?
@mikejritter tested against a local instance

[ray-lee]

Looks good.