Update fb_magma_knf to fix issues in orc8r helm chart

Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>

magma/fb_magma_knf/helm-chart-v3s/orc8r/charts/postgresql/ci/default-values.yaml

+# Leave this file empty to ensure that CI runs builds against the default configuration in values.yaml.

magma/fb_magma_knf/helm-chart-v3s/orc8r/charts/postgresql/ci/shmvolume-disabled-values.yaml

+shmVolume:
+  enabled: false

magma/fb_magma_knf/helm-chart-v3s/orc8r/charts/postgresql/files/README.md

+Copy here your postgresql.conf and/or pg_hba.conf files to use it as a config map.

magma/fb_magma_knf/helm-chart-v3s/orc8r/charts/postgresql/files/conf.d/README.md

+If you don't want to provide the whole configuration file and only specify certain parameters, you can copy here your extended `.conf` files.
+These files will be injected as a config maps and add/overwrite the default configuration using the `include_dir` directive that allows settings to be loaded from files other than the default `postgresql.conf`.
+
+More info in the [bitnami-docker-postgresql README](https://github.com/bitnami/bitnami-docker-postgresql#configuration-file).