Add deprecation note for `includeClassProperties` in `api/Class/v1`

Hi! `includeClassProperties` option is deprecated now, but it's really hard to discover that it is - I was only able to find this information when I've got an 429 Too Many Requests with the following `message` in json:

> Option 'IncludeClassProperties' is deprecated. Use api/class/properties/v1 for better performance and higher rate limit. Try again in 4 seconds.

It would be great if this can be communicated somewhere also - e.g. in the OpenAPI schema description, a note that field is deprecated and rate limit is lowered if someone is using it.

https://github.com/buildingSMART/bSDD/blob/6d5c3be598a5cb0c298287d99387c7a8616ccc2d/Documentation/bSDD%20OpenAPI.yaml#L52-L56

And any information when it's planned to be removed, in `api/Class/v2`?

Start with Documentation/bSDD OpenAPI.yaml around lines 52-56 and review how the api/Class/v1 option is described. Update the schema documentation to identify includeClassProperties as deprecated and explain the rate-limit impact, then clarify the planned removal timing for api/Class/v2 if that information is available.】【。

Written by the indexing model from the issue text.