Fix #1169; Add updated named link for QCS access

[amyfbrown]

Description

This pull request fixes #1169 by adding a named, updated QCS signup link.

Checklist

• The above description motivates these changes.
• There is a unit test that covers these changes. not applicable
• All new and existing tests pass locally and on Travis CI. not applicable
• Parameters and return values have type hints with PEP 484 syntax. not applicable
• Functions and classes have useful Sphinx-style docstrings. not applicable
• All code follows Black style and obeys flake8 conventions. not applicable
• (New Feature) The docs have been updated accordingly. not applicable
• (Bugfix) The associated issue is referenced above using auto-close keywords.
• The changelog is updated, including author and PR number (@username, gh-xxx).

[braised-babbage]

👍

[appleby]

lgtm thanks!