Persist "Pin sidebar"

[paulo-graca]

Describe the bug

If the user pins the sidebar and do a refresh, the sidebar doesn't persist opened.

To Reproduce

Steps to reproduce the behavior:

1. If you click "pin sidebar"
2. and for any reason do a refresh
3. the sidebar returns to the collapsed position

Expected behavior

If the user pins the sidebar, it should be always opened until the user chooses to unpin. Along with the language setting, perhaps a cookie might be useful.