feat: auto generated files and new structure (#4)

## Description

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At least please give us some description what you are trying to achieve and why your change is needed. -->

relates to #1234

## Checklist

- [ ] Issue was linked above
- [ ] Code format was applied: `make fmt`
- [ ] Examples were added / adjusted (see `examples/` directory)
- [x] Docs are up-to-date: `make generate-docs` (will be checked by CI)
- [ ] Unit tests got implemented or updated
- [ ] Acceptance tests got implemented or updated (see e.g. [here](f5f99d1709/stackit/internal/services/dns/dns_acc_test.go))
- [x] Unit tests are passing: `make test` (will be checked by CI)
- [x] No linter issues: `make lint` (will be checked by CI)

Reviewed-on: #4
Reviewed-by: Andre_Harms <andre.harms@stackit.cloud>
Co-authored-by: Marcel S. Henselin <marcel.henselin@stackit.cloud>
Co-committed-by: Marcel S. Henselin <marcel.henselin@stackit.cloud>

docs/data-sources/postgresflexalpha_database.md

@@ -25,16 +25,16 @@ data "stackitprivatepreview_postgresflexalpha_database" "example" {
 
 ### Required
 
-- `database_id` (String) Database ID.
 - `instance_id` (String) ID of the Postgres Flex instance.
 - `project_id` (String) STACKIT project ID to which the instance is associated.
 
 ### Optional
 
+- `database_id` (Number) Database ID.
+- `name` (String) Database name.
 - `region` (String) The resource region. If not defined, the provider region is used.
 
 ### Read-Only
 
 - `id` (String) Terraform's internal resource ID. It is structured as "`project_id`,`region`,`instance_id`,`database_id`".
-- `name` (String) Database name.
 - `owner` (String) Username of the database owner.