use clickhouse-server container image instead of clickhouse-client

[CaptTofu]

1. clickhouse-client container for the cron job wouldn't run in aws-dev-eu, which uses arm64, switched to clickhouse-server container and it works
2. Added more information and elaboration for the backup process using the operator

[CaptTofu]

Re-created this PR because when I rebased my fork with master, somehow it pulled in recent changes which showed up in the original PR.

[coveralls]

Pull Request Test Coverage Report for Build 13054457545

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 278 unchanged lines in 11 files lost coverage.
• Overall coverage decreased (-2.0%) to 66.306%

---

Files with Coverage Reduction	New Missed Lines	%
pkg/clickhouse/clickhouse.go	2	73.84%
cmd/clickhouse-backup/main.go	2	79.69%
pkg/storage/object_disk/object_disk.go	7	68.38%
pkg/config/config.go	8	73.23%
pkg/status/status.go	9	70.2%
pkg/backup/restore.go	9	67.46%
pkg/backup/backuper.go	17	70.92%
pkg/server/server.go	18	58.0%
pkg/storage/general.go	20	59.6%
pkg/storage/s3.go	25	45.98%

Totals
Change from base Build 13015073872:	-2.0%
Covered Lines:	9249
Relevant Lines:	13949

---

💛 - Coveralls

[Slach]

old clickhouse-client should works with new clickhouse-server
which kind of issue you got here?

[Slach]

ok. got it
https://hub.docker.com/r/clickhouse/clickhouse-client/tags
doesn't support arm64
let's add comment here

[Slach]

thanks for contribution