Change black/white listed names

In order to remove the racial connotations of Whitelist/Blacklist, we'd like to change for Safelist/Blocklist in our documentation (we've already done in the code #504 (closed)). It's not a new or original idea; saw for example https://github.com/rack/rack-attack/pull/181.

That appears in:

• doc/content/en/08-stackgres-web-api/01-error-types/_index.md
• doc/content/en/06-crd-reference/03-sgpostgresconfig/_index.md
• stackgres-k8s/src/common/src/main/java/io/stackgres/common/ErrorType.java
• stackgres-k8s/src/operator/src/test/java/io/stackgres/operator/validation/pgconfig/BlocklistValidatorTest.java
• stackgres-k8s/src/operator/src/main/java/io/stackgres/operator/validation/pgconfig/BlocklistValidator.java
• stackgres-k8s/src/operator/src/main/java/io/stackgres/operator/patroni/factory/PatroniEndpoints.java
• stackgres-k8s/src/operator/src/main/java/io/stackgres/operator/sidecars/pooling/PgPooling.java