Replace content block label with descriptive text

[ggeisler]

Descriptive summary

The content block configuration pages currently contain a redundant label. To be more useful to the administrator, we should replace the label with a brief description of the purpose of the content block.

Expected behavior

As an Admin, when I go to configure a content block I should understand what that content block is for.

Actual behavior

When I go to configure a content block I see a label that repeats the name of the tab just above it and I don't get any hint about the purpose of the content block.

Steps to reproduce the behavior

1. Go to Administration
2. Go to Configuration > Settings > Content Blocks
3. Pick any tab and look at the top part of the page

Suggestion

1. Remove the redundant label from each of the content block pages.
2. Add a brief description conveying the purpose of the content block. Suggestions for the description text for each page:

About page If you enable the display of the About page, the content below is used to populate it.

Announcement text The Announcement text block is displayed immediately below the repository site banner, with a colored background, spanning the full width of the page.

Marketing text The Marketing text block is displayed below the repository site banner, spanning the full width of the normal content area of the page.

Featured researcher The Featured Researcher text block is displayed in a tab on the right-side of the bottom half of the repository home page.

As an example (the display checkbox is not currently in the code, but is suggested in #813):

[jcoyne]

I believe the label was there for accessibility guidelines.

[ggeisler]

I don't get hear any different behavior from ChromeVox when I remove it. I'm no accessibility expert, though. But at the least it seems like it should be .sr-only.

[mjgiarlo]

@ggeisler OK. Sounds good.