Standardize Edit Pencil Icon Behavior

[edschema]

Description
The pencil icon is used on block headers to mean "rename block" or "open xblock editor" depending on the context.

Outline Page	Local blocks/ editable library blocks	Un-editable library blocks

Desired Behavior
We should standardize the button behavior and tooltip text:

• follow the behavior on the outline page: upon hover show a pencil icon with a tooltip "Rename" that is directly adjacent to the title
• For content blocks that are editable: edit icon persists on the right hand side as it currently does with a tooltip "Edit "
• For content blocks that are NOT editable: edit icon persists in an inactive state with tooltip "Cannot edit this block"

[jristau1984]

Standardizing sounds great! edx.org did this with our instance by having an "EDIT" button for going to the editor, and pencil for title changes.