Make the default GroupBy attributes customizable

[alexbikfalvi]

User problem

In Explore Traces, traces can be grouped using the Group By. At this moment for us by default Group By shows two default label cluster and environment. However, users may have a different attribute resource.some_env to actually representing the environment for the traces and there is no environment for the traces.

As the environment shows as default in Group By, our users try to group the traces based on environment and get an empty result which is confusing for them. In my opinion, having some default is completely fine but having an irrelevant (environment) default value is confusing for general users.

Users think it would be less confusing for users if the Group By section is grayed out with an example option instead of a button (cluster, environment) which convinces them that these are valid values for our data. Otherwise if they could have only default values that are relevant to their traces that would also help.

What is the problem the customer is trying to solve

Improve the defaults to make it easier for their users as they don't use any of the values we include in our defaults.