Logging and error handling improvements, bug fixes (#21)

- Uniformed logs and diagnostics:
  - Logging and adding to diagnostics is done by the highest level function (Create/Read/Update/Delete/Import) using `LogAndAddError`
  - Lower-level routines' signature changed to return error instead of writing to diagnostics
  - Standardize summary and details across services
  - Removed manual adding of relevant variables to details (they're in the context, TF adds them to logs)
- Changed validators to be closer to official implementation
- Fix logging wrong output after wait
- Fix Argus checking wrong diagnostics
- Fix Resource Manager not updating state after project update
- Fix unnecessary pointer in LogAndAddError

docs/data-sources/logme_instance.md

@@ -33,7 +33,7 @@ data "stackit_logme_instance" "example" {
 - `cf_organization_guid` (String)
 - `cf_space_guid` (String)
 - `dashboard_url` (String)
-- `id` (String) Terraform's internal resource identifier. It is structured as "`project_id`,`zone_id`".
+- `id` (String) Terraform's internal resource identifier. It is structured as "`project_id`,`instance_id`".
 - `image_url` (String)
 - `name` (String) Instance name.
 - `parameters` (Attributes) (see [below for nested schema](#nestedatt--parameters))

docs/data-sources/mariadb_credentials.md

@@ -34,7 +34,7 @@ data "stackit_mariadb_credentials" "example" {
 - `host` (String)
 - `hosts` (List of String)
 - `http_api_uri` (String)
-- `id` (String) Terraform's internal resource ID. It is structured as "`project_id`,`instance_id`,`credentials_id`".
+- `id` (String) Terraform's internal resource identifier. It is structured as "`project_id`,`instance_id`,`credentials_id`".
 - `name` (String)
 - `password` (String, Sensitive)
 - `port` (Number)

docs/data-sources/mariadb_instance.md

@@ -33,7 +33,7 @@ data "stackit_mariadb_instance" "example" {
 - `cf_organization_guid` (String)
 - `cf_space_guid` (String)
 - `dashboard_url` (String)
-- `id` (String) Terraform's internal resource ID. It is structured as "`project_id`,`instance_id`".
+- `id` (String) Terraform's internal resource identifier. It is structured as "`project_id`,`instance_id`".
 - `image_url` (String)
 - `name` (String) Instance name.
 - `parameters` (Attributes) (see [below for nested schema](#nestedatt--parameters))

docs/resources/mariadb_credentials.md

@@ -33,7 +33,7 @@ resource "stackit_mariadb_credentials" "example" {
 - `host` (String)
 - `hosts` (List of String)
 - `http_api_uri` (String)
-- `id` (String) Terraform's internal resource ID. It is structured as "`project_id`,`instance_id`,`credentials_id`".
+- `id` (String) Terraform's internal resource identifier. It is structured as "`project_id`,`instance_id`,`credentials_id`".
 - `name` (String)
 - `password` (String, Sensitive)
 - `port` (Number)