Update grafana with edits made in Replicated Ship Cloud

[replicated-ship]

Release notes:

[stable/grafana] Allow secrets for sidecar (helm#13492) (helm#15331)

• [stable/grafana] Allow secrets for sidecar ([stable/grafana] datasource provisioning with sidecar should be done trough secrets helm/charts#13492)

Updated the sidecar image to version 0.0.18
This allows also using secrets for volume mounts
This way the dashboard and datasource import can be extended to those
datatypes

Signed-off-by: Sergej Herbert [email protected]

• [stable/grafana] Allow secret - review ([stable/grafana] datasource provisioning with sidecar should be done trough secrets helm/charts#13492)

• keep the appVersion the same
• bump minor version
• add missing apostrophe

Signed-off-by: Sergej Herbert [email protected]

• [stable/grafana] Allow secret - review Add grafana version 3.3.1 from Replicated Ship Cloud #2 ([stable/grafana] datasource provisioning with sidecar should be done trough secrets helm/charts#13492)

• enable sidecar resource secrets and configmaps by default
• update readme to indicate secret preference for datasources

Signed-off-by: Sergej Herbert [email protected]