An OSS read-only user should be able to list measurements on a database

[rbetts]

Proposal

From the Chrongraf Data Explorer page... it shows me a list of databases, and I can click on one and it gives me a really handy view of the measurements (which you can click to see tags, etc.).

Current behavior:
However, if I connect to the data source with an account that only has READ privileges, it doesn’t do that. I can run queries just fine, but I don’t get that handy “tool” (see screenshot below)…

Desired behavior:

Should be able to issue SHOW commands without requiring admin write permissions.

Use case: [Why is this important (helps with prioritizing requests)]
Allows READ only database users to use Chronograf Data Exploration page.

See: https://community.influxdata.com/t/cant-see-measurements-list-if-non-admin-user/2142