Introduce the concept of Deprecated and Internal Macros

Use case:

• For example we have {{spaceindex/}} and {{spaces/}} macros that are deprecated now (since the addition of Nested Pages).
• They still appear in the Macro browser, "polluting" the list and tempting users to use them.

Some ideas:

• Have a Deprecated category and show that visibly to the user when that's the case.
• Don't show deprecated in the initial list
• Only show deprecated macros to advanced users
• Have a checkbox to not show deprecated macros and have it checked by default