Honor whatever the space attribute is set as, ID/UUID or name.

[mars]

Fix for issue where setting Space references as an ID/UUID will cause churn in the config, triggering recreation of susceptible resources on every apply.

Changes heroku_space_inbound_ruleset and heroku_space_app_access to honor whatever space identifier is set by the configuration, either ID/UUID or name, instead of resetting it back to name.

[wchrisjohnson]

@mars Inn light of #332, how do you feel about this in that context? Or is this just a first step toward getting to that eventual end?

[mars]

@wchrisjohnson We can definitely go a step further from this, and enforce Spaces by ID using a similar breaking, major version migration as that #332 Apps by ID.

Given the urgency for some existing users, this fix should resolve the immediate problem without forcing a major version release and manual config migration steps for everyone.