add documentation for coordinator dynamic configuration

[clintropolis]

Docs were missing, also fixed an error in overlord dynamic config example

[techdocsmith]

Seems odd not to have the payload here, but I see that it is in the linked section. Might be worth a mention to get the payload there?

[capistrant]

I'm indifferent on this note. Since other POST endpoints in this same doc do not include information on what the payload would look like, I think it is fine as is. (this is a reply to another review comment: #11052 (comment))

[techdocsmith]

Thanks @capistrant ! I think you are right, too. Everything API related in Druid could use an overhaul to be a little more user-friendly and that surely wasn't the goal of this PR.

[clintropolis]

Ah yeah, I just copied this from the overlord section. It would be really nice to have example requests and responses for all of these API calls, but I think maybe that could be done as future work.

[capistrant]

I'm indifferent on this note. Since other POST endpoints in this same doc do not include information on what the payload would look like, I think it is fine as is. (this is a reply to another review comment: #11052 (comment))

[capistrant]

I see that console is having some CI issues on this and another docs related PR, #11053. The docs job within CI passed for both though. Haven't had a chance to cross check these CI stages with other PRs to see if they are broken everywhere.

[clintropolis]

I see that console is having some CI issues on this and another docs related PR, #11053. The docs job within CI passed for both though. Haven't had a chance to cross check these CI stages with other PRs to see if they are broken everywhere.

I think it was some sort of strange travis caching issue, since I saw it on some non doc related PRs too. I think I resolved it by side-effect with #11057 (seemed easier to do this than hunt down and delete all the caches in travis), so when we retry CI it should be working now. I restarted on this PR just for fun to test this theory.