Fetch inject configuration from control plane

[grampelberg]

What problem are you trying to solve?

As the configuration for install continues to grow, it is becoming difficult to know what flags to set in inject to match the control plane features. As an example, see #1887 and #1891 .

How should the problem be solved?

Update the inject command to pull default configuration from the control plane before actually doing the inject.

Any alternatives you've considered?

• A local configuration file (see Work with --linkerd-namespace more seamlessly #1892 and Version check in the CLI #1604). This will work for the single situation, but not for multiple users of the same control plane.

[klingerf]

@olix0r is working on this in #2434, but the implementation will change once the config endpoint has been added (#2455). Assigning to him.

[alpeb]

Closed via #2535