Reordering Contexts in larger installations slow and results to thousands of unnecessary queries

[ajnyga]

Describe the bug
When an installation has a large number of contexts, reordering the list of contexts becomes slow. This is because saving the new order will result to resaving all context settings table data, not only the new order. The reordering therefore triggers thousands of queries leading to slow performance. With 150 journals it can take up to 60 seconds for the new order to be stored.

We should just update the new sequence and not touch the settings data.

To Reproduce
Steps to reproduce the behavior:

1. Start query logging
2. Go to Administration > Hosted journals
3. Click on 'Order'
4. Reorder contexts
5. Hit Done, see results in query log

What application are you using?
OJS, OMP and OPS all versions 3.0+

Additional information
Related code
https://github.com/pkp/pkp-lib/blob/main/controllers/grid/admin/context/ContextGridHandler.php#L155-L163