add reasonable adjustments page

[KatrionaGoldmann]

Summary

Adding information about reasonable adjustment policy.

Related issues

• Closes #159

[phinate]

This isn't us, but when the request doesn't fall under reasonable adjustments, you need to go via Access to Work. Should we link that here?

[penelopeysm]

.. That was a cryptic review wasn't it.

@phinate feel free to make changes / suggestions and we can merge once you're happy