Remove incorrect or too restrictive validations

[steinmn]

Validation of ChargerLocalSettings-response:
We don't use the response for anything, and it is an undocumented API, so we shouldn't require any validation.

Validation of Installation(s)-response:
Users without the Owner role don't get the full installation object, specifically not the AuthenticationType-entry that was in the validation. Since the Installations-response includes all installations the user has access to, not just the one(s) they have added to HA, that causes issues. Since we don't use Authentication type for anything (other than displaying it in a sensor), we can just remove the requirement.

Fixes #354. Fixes #357

[steinmn]

Addresses #354

Given that this issue only applies to the cable lock and the HMI-brightness, I don't think it is critical enough to warrant an immediate release, I think we can leave it for a bit and see if any additional issues pop up.

[steinmn]

Added validation-relaxing for Installation to address #357 as well. I think this one is severe enough for another release. Do you think we need a more thorough review of the validation models to see if we really need the values we have set as required @sveinse?

[sveinse]

LGTM

But as mentioned, we shouldn't validate anything except the data we use in the integration. I.e. the point of validation is to prevent error deeper in the integration, not check all of Zaptec's data.