[bitnami/kong] readme: add dbless mode infos (#5804)

* readme: add dbless mode infos

* fix readme

* bump version

* Update bitnami/kong/README.md

Co-authored-by: Carlos Rodríguez Hernández <carrodher1179@gmail.com>

* Bump version

* Update README.md

Co-authored-by: Carlos Rodríguez Hernández <carrodher1179@gmail.com>
Co-authored-by: Carlos Rodríguez Hernández <carlosrh@vmware.com>

bitnami/kong/Chart.yaml

@@ -34,4 +34,4 @@ name: kong
 sources:
   - https://github.com/bitnami/bitnami-docker-kong
   - https://konghq.com/
-version: 3.4.5
+version: 3.4.6

bitnami/kong/README.md

@@ -311,6 +311,21 @@ The Bitnami Kong chart allows setting two database backends: PostgreSQL or Cassa
     --set cassandra.external.password=_PASSWORD_OF_YOUR_CASSANDRA_INSTALLATION_
 ```
 
+### DB-less
+
+Kong 1.1 added the capability to run Kong without a database, using only in-memory storage for entities: we call this DB-less mode. When running Kong DB-less, the configuration of entities is done in a second configuration file, in YAML or JSON, using declarative configuration (ref. [Link](https://docs.konghq.com/gateway-oss/1.1.x/db-less-and-declarative-config/)).
+As is said in step 4 of [kong official docker installation](https://docs.konghq.com/install/docker#db-less-mode), just add the env variable "KONG_DATABASE=off".
+
+#### How to enable it
+
+1. Set `database` value with any value other than "postgresql" or "cassandra". For example `database: "off"`
+2. Use `kong.extraEnvVars` value to set the `KONG_DATABASE` environment variable:
+```yaml
+kong.extraEnvVars:
+- name: KONG_DATABASE
+  value: "off"
+```
+
 ### Sidecars and Init Containers
 
 If you have a need for additional containers to run within the same pod as Kong (e.g. an additional metrics or logging exporter), you can do so via the `sidecars` config parameter. Simply define your container according to the Kubernetes container spec.