Downgrade from Database 7.1.0 to 7.0.0

Configuration changes

Replace the flush-size namespace configuration parameter with an explicit write-block-size 8M. In Database 7.1.0 and later the write-block-size was pinned to 8MiB. To reduce it, zeroize the drives on each downgraded node before restarting it. If you do not explicitly adjust the write-block-size correctly, it will implicitly be assigned a 1MiB value, which is smaller than the 8MiB storage. This will manifest in the following error on startup:
```
May 19 2024 17:26:14 GMT: INFO (drv_ssd): (drv_ssd.c:1056) /test/dev/xvdf has 5120 wblocks of size 1048576 May 19 2024 17:26:14 GMT: CRITICAL (drv_ssd): (drv_ssd.c:2390) /test/dev/xvdf: can't change write-block-size from 8388608 to 1048576
```
Replace your post-write-cache namespace configuration parameter with a post-write-queue. If you keep your write-block-size at 8MiB, you can divide the post-write-cache by 8MiB to get the number of write-blocks to cache.
Remove any configuration parameters added in Database 7.1.0 from your configuration file: default-password-file, indexes-memory-budget, evict-indexes-memory-pct, default-read-touch-ttl-pct, auto-revive, tls-refresh-period, batch-max-requests.