Add fusion auth reactor resource

[einal3m]

This PR adds the FusionAuth reactor as a terraform resource.

The reactor apis aren't standard CRUD apis, so this implementation is a little different:

• The create and update methods both use the same POST api to update the license attributes
• The read method can't update the state when the reactor is licensed, since the GET api doesn't include the license attributes
• The create method doesn't return the id of the reactor (aka fusion auth instance) so I have made up an id. I think this will be ok, since there can be only one reactor.

I've left some comments in the code where things are a little different than for a normal resource.

[einal3m]

Both the create and update paths use the ActivateReactor method.

There really is no "create" endpoint for the reactor because it always exists, this endpoint sets the license data (for the first time or any subsequent times).

[einal3m]

During local testing we discovered that the terraform state got updated even if the resource failed to update in FusionAuth. This is true of other resources too (we check with the webhook). After a little googling, we discovered this little snippet of code data.Partial(true) which tells terraform that something went wrong and not to update the state.

[robotdan]

Thanks for the contribution @melm73.

I don't have any strong opinions here, and I am not a Terraform expert, so feel free to ignore my comments.

Since this isn't really a traditional CRUD as @melm73 mentions - would it read better to use function names such as:

• activate() This could in theory replace both createReactor and updateReactor since the only two states are licensed and un-licensed, so updating just re-activates with a different license key.
• decommission() Depends on how far we want to go with the Nuclear Reactor theme. 😁Could also use deactivate.
• status() The read operation currently returns the license status of the FusionAuth instance.

[MCBrandenburg]

@melm73 thanks for your contributions. Pushing this and building v0.1.59