feat(rust): integrate space's subscription data in command

[adrianbenavides]

Adds the subscription data to the space, status and enroll commands. This PR also improves the output construction of those commands, which led me to improve the Output trait.

Changes to the Output trait

In this PR you can see that the Subscription struct is used in three different kinds of outputs (see images below for examples):

1. As a standalone item (it's individual representation)
2. As part of other structs in their individual representation (e.g. in the space show command)
3. As part of other structs in their list representation (e.g. in the space list command)

Now, we want to reuse the output of the individual representation, but there are some differences we need to keep in mind: in 2. the subscription is padded + indented; in 3. the subscription is padded.

The Output trait lets you define the output for 1. and 3. but not for 2. and, in this case, the only difference between them is the left spacing. And I think this is also true for a lot of other structs.

That being said, I've extended the Output trait a little to make these "left-spacing" transformations easier. You can check the Subscription struct as an example of how to reuse the Display representation and how it's also integrated in the Space's Display impl.

enroll

Free trial + and the space has been just created:

Free trial + the space already existed:

Not a free trial subscription:

space and status

[etorreborre]

Some of my comments can definitely be addressed in other PRs. My biggest concern is with inlining the whole Subscription data into one row cell.

[etorreborre]

Thanks for all the changes 🏵️