Merge list & freeze commands

[xavfernandez]

What's the problem this feature will solve?

Simplify pip CLI interface.

Currently, list and freeze are two commands that perform almost the same role.
pip freeze and pip list output the same kind of information on the installed packages but with different format and different available options.

As an example, pip freeze --all should produce the same output as pip list --format=freeze (except for editable installs...).

Describe the solution you'd like

Both commands would be merged into one (list) and freeze would simply be an alias for list --format=freeze.
This should lower the maintenance and simplify our CLI interface.

Alternative Solutions
Statu quo.

[pradyunsg]

Color me interested.

I think we'd want a decently long deprecation cycle on this though -- ~1.5 years or so?

[chrahunt]

Regarding deprecation, you're referring to the freeze subcommand, after spending 1.5 years as an alias?

[xavfernandez]

I did not plan on removing the freeze command but it would certainly make sense, with a very very long deprecation period indeed.