Terraform provider to manage InfluxDB database/user

__Proposal:__
Terraform provider to manage InfluxDB database/user, for both OSS and Enterprise

__Current behavior:__
only API is supported

__Desired behavior:__
define InfluxDB database/user as Code, including retention policy, permissions

__Alternatives considered:__
Hashicorp had one but now it is deprecated
https://github.com/hashicorp/terraform-provider-influxdb

__Use case:__
Currently with InfluxDB Cloud 1.0, we are managing database and users manually. The change is not peer reviewed and the config is not reproducible for Disaster Recovery

Start by reviewing the requested Terraform provider scope and the deprecated Hashicorp provider linked in the issue. Determine how database, user, retention-policy, and permission management should cover both InfluxDB OSS and Enterprise, with reproducible configuration for disaster recovery. Done means the provider can manage those resources rather than requiring manual API-only changes.

Written by the indexing model from the issue text.