Add clickhouse-cluster-config to omdb blueprint output

[andrewjstone]

Print clickhouse cluster config related tables for blueprint show and
blueprint diff omdb commands.

A bunch of the complexity and duplication here arises from the fact
that we are diffing not only between blueprints that have identical
structures, but between blueprints and collections that have
drastically different contents. This is useful, but we probably should
consider separating the two types of diffs and reworking all the
blueprint diff logic to use some sort of semantic diff between types
such as https://github.com/distil/diffus as recommended by @sunshowers.

In order to make the cluster_secret UUID generation deterministic for
tests I had use an rng seed in the BlueprintBuilder. This required moving
creation of the initial ClickhouseClusterConfig and it's wrapping
ClickhouseAllocator from BlueprintBuilder::new_based_on to
BlueprintBuilder::build.

Fixes #6941

[andrewjstone]

Fixes ##6941

[andrewjstone]

Expectorate tests added. Ready for review.

[jgallagher]

Sorry for the long wait on this one! LGTM

[jgallagher]

Tiny nit - I think this could be

Suggested change

	let Some(config) = &self.blueprint.clickhouse_cluster_config else {
	return None;
	};
	let config = self.blueprint.clickhouse_cluster_config.as_ref()?;

[andrewjstone]

Silly me. Thanks! Fixed in 81e85f5

[jgallagher]

I haven't looked at ClickhouseClusterConfigDiffTables yet, but leaving a note mostly for myself for when I get to it: could it return a different type so we don't have to unwrap here?

Edit: followed up in #6968 (comment)

[jgallagher]

I'd vote yes on this, I think? Nothing in this table is sled-specific, AFAICT; it's more like BpGenerationTable or something.

[andrewjstone]

I'd vote yes on this, I think? Nothing in this table is sled-specific, AFAICT; it's more like BpGenerationTable or something.

Done in f0ae7db

I thought this was going to be a larger change. I liked BpGenerationTable, but went with the shorter BpTable because of the ripple of changes to other type names.

[jgallagher]

W.r.t. my question earlier about the unwrap; I think the situation is:

• The only method that doesn't fill in ClickhouseClusterConfigDiffTables::servers is removed_from_collection()
• make_clickhouse_cluster_config_diff_tables() can therefore also return a servers value of None

I guess we could make a second diff table type where servers is not optional, return it from all the methods except this one and removed_from_collection(), and add a From impl to convert it into ClickhouseClusterConfigDiffTables? Doesn't seem terrible, but does seem like a fair bit of busywork to avoid a single .unwrap(). I'd probably do it, but if you'd rather not that's fine with me.

[andrewjstone]

Thanks for the suggestion @jgallagher. I was unhappy with this unwrap as well, especially since the SAFETY message would become invalid if someone changed a method far away from that message.

Fix made in 81e85f5