`IsUpToDate` should exclude `unset` fields

Context

In a take-over scenario existing resource - (import) - resource represented by an CR - (take over), we need to make sure that the controller does not override settings of external resource by accident.

This requires that "IsUpToDate" only check fields that are explicitly set in the CR.

Technical Steps

Compare a forProvider field only when it is explicitly provided.

Example: space

• Before: This implementation does not distinguish unset and default thus could disable ssh for an exiting space.

func IsUpToDate(spec v1alpha1.SpaceParameters, observed *resource.Space, ssh bool) bool {
	return spec.Name == observed.Name && spec.AllowSSH == ssh
}

• After:

func IsUpToDate(spec v1alpha1.SpaceParameters, observed *resource.Space, ssh bool) bool {
	if spec.AllowSSH != nil && *spec.AllowSSH != ssh {
		return false
	}
	return spec.Name == observed.Name 

** Alternative **

• We always late initialize unset fields according to the current state before calling drift detection.

Required Steps

• Review all resources IsUpToDate implementations

Acceptance Criteria

• Create followup items in IsUpToDate fields that need to be improved

Review every IsUpToDate implementation and the related forProvider fields, starting with the SpaceParameters example in the issue. Compare how unset fields are handled and record follow-up items for each field that needs improvement. Done means all resources have been reviewed and the required follow-up items are created.