* gundeck/cassandra: TWCS for 'notifications' table
In Gundeck's 'notifications' cassandra table, switch to [TWCS](https://cassandra.apache.org/doc/latest/cassandra/operating/compaction/twcs.html) compaction strategy, which should be more efficient for this workload, and possibly bring performance benefits to latencies.
It may be beneficial to run a manual compaction before rolling out this
change (but things should also work without this manual operation).
In case you have time, run the following before deploying this update:
```
nodetool compact gundeck notifications
```
Co-authored-by: Akshay Mankar <[email protected]>
