Cluster configuration updates

[aarohib]

What does this PR do?

• Updates the Clusters concept structuring
• Adds Cluster configuration detail to the Clusters concept
• Adds dynamic configuration reference
• Fills out Cluster configuration (static) reference (See archival, namespaceDefaults, dcReplication, dynamicConfigClient)
• Links between concepts and how-tos and a few other related changes to help connect the information.
• Also updates no. of Signals limit on Temporal Cloud (EDU-726). Context: https://temporaltechnologies.slack.com/archives/C03AGLU5JEQ/p1686277047099249?thread_ts=1686154547.368759&cid=C03AGLU5JEQ

Notes to reviewers

Thank you for taking the time to review this PR!

• All files under the docs folder are generated guides and not specific to the updates made in this PR. You can skip reviewing them.
• Changed files that need a review in this PR are under docs-src/clusters, docs-src/concepts, docs-src/references, and kb.
• concepts/what-is-cluster-security-configuration and concepts/what-is-cluster-obervability are just new files that rehome currently published content and were created to reorganize the Cluster concept so the info flows better. Changes in these files are not a priority in this update (but I'm happy to make any pressing updates to incorrect info).

[aarohib]

@dnr and @yycptt
Since this is a long thread and missing comments is easier than finding them, here is a list of comment threads that I need responses on:

• Cluster configuration updates #2029 (comment)
• Cluster configuration updates #2029 (comment)
• Cluster configuration updates #2029 (comment)

[dnr]

dynamic config stuff looks good to me

[yycptt]

+1, configuration part looks good!

[djmagee]

Three nits, and this is good to go!

[flossypurse]

Nice @aarohib !