Duplication of required properties in OctopusDeploySettings

Created as a result of changes in #990

Since the `OctoPush` alias takes the `server` and `apiKey` in the parameter, this effectively replaces/duplicates the same properties in the `OctopusDeploySettings` class.

However, the options in this calls are currently used by the `OctoCreateRelease` aliases. Therefore, to make required properties clearer to the user, we should deprecate/obsolete the existing alias in favour of a new one that takes required properties directly. Finally, these properties can be removed from the `OctopusDeploySettings` class.

Happy to take corrections or suggestions on the above approach.

Start by locating OctopusDeploySettings, the OctoPush alias, and the OctoCreateRelease aliases referenced in the issue. Compare where server and apiKey are currently supplied, then review the surrounding tests or alias usage before deciding how deprecation and removal should be handled. Done means required properties are exposed clearly without duplicated settings and existing release behavior remains covered.

Written by the indexing model from the issue text.