[ENH] - Make logs more user-friendly

[nkaretnikov]

Feature description

This has two subtasks:

• Explain how to interpret the output of conda config and the strict channel priority. Users only look at the config output and overlook CONDA_FLAGS=--strict-channel-priority. The latter is what actually determines the channel priority in conda-store. Add a very visible message before the config output is printed in the logs explaining this.

• Print action end time and time delta. This probably should be done with a context manager where ActionContext is defined, so it automatically applies to all actions.

Value and/or benefit

Improved UX.

Anything else?

No response