API docs: Add certificates to host vitals for macOS, iOS, iPadOS

[gillespi314]

For #23235

Add endpoints to get list of installed certificates by host id and device identifier. This list will be available for macOS, iOS, and iPadOS hosts. It will be empty for other platforms.

NOTE: See also #26457 for additional sort params.

[gillespi314]

@rachaelshaw @georgekarrv, now that the certificates have their own endpoints, I think we need to specify the expected response if an API user requests certificates for a host that is not macOS, iOS, or iPadOS. My initial thought is that we would just return 200 with an empty {} as the JSON body. What do you think?

[rachaelshaw]

My initial thought is that we would just return 200 with an empty {} as the JSON body. What do you think?

@gillespi314 makes sense to me more than erroring, since we may add them later.

Thoughts on returning an empty certificates array instead of just {}?

[gillespi314]

My initial thought is that we would just return 200 with an empty {} as the JSON body. What do you think?

@gillespi314 makes sense to me more than erroring, since we may add them later.

Thoughts on returning an empty certificates array instead of just {}?

Good idea, I like that better.