[cetic/fadi] InfluxDB V2 support

[zakaria2905]

Here we will track the V2 update of InfluxDB helm chart:

https://github.com/influxdata/helm-charts/tree/master/charts/influxdb2

[banzo]

When upgrading the deployment with Helm, the upgrade fails.

Steps to reproduce:

git clone https://github.com/cetic/helm-fadi.git
cd helm-fadi
minikube start
vim values.yaml # just enable influxdb
helm dep up
helm install idb .
helm upgrade idb .

The last command will trigger the following error message:

Error: UPGRADE FAILED: template: fadi/charts/influxdb/templates/NOTES.txt:199:4: executing "fadi/charts/influxdb/templates/NOTES.txt" at <include "common.errors.upgrade.passwords.empty" (dict "validationErrors" $passwordValidationErrors "context" $)>: error calling include: template: fadi/charts/influxdb/charts/common/templates/_errors.tpl:21:48: executing "common.errors.upgrade.passwords.empty" at <fail>: error calling fail: 
PASSWORDS ERROR: You must provide your current passwords when upgrading the release.
                 Note that even after reinstallation, old credentials may be needed as they may be kept in persistent volume claims.
                 Further information can be obtained at https://docs.bitnami.com/general/how-to/troubleshoot-helm-chart-issues/#credential-errors-while-upgrading-chart-releases

    'auth.admin.password' must not be empty, please add '--set auth.admin.password=$ADMIN_USER_PASSWORD' to the command. To get the current value:

        export ADMIN_USER_PASSWORD=$(kubectl get secret --namespace "default" idb-influxdb -o jsonpath="{.data.admin-user-password}" | base64 --decode)

    'auth.admin.token' must not be empty, please add '--set auth.admin.token=$ADMIN_USER_TOKEN' to the command. To get the current value:

        export ADMIN_USER_TOKEN=$(kubectl get secret --namespace "default" idb-influxdb -o jsonpath="{.data.admin-user-token}" | base64 --decode)

[banzo]

Related documentation at cetic/fadi#149

[banzo]

@zakaria2905 can we add some doc on how to use the first token for the upgrade.