DOC/CI: Use more explicit data setup in user guides
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).

Should fix the current CI failure for the docbuild.

* Use more explicit setup in `io.rst` instead of files / `:suppress:`
* Remove some static files that are no longer needed after refactor

Also fixes CI failure in the Np Dev build
@jreback all green Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

```
git checkout 1.4.x
git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
git cherry-pick -x -m1 339623b58abda42907f3090769d07c663e74a796
```

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

```
git commit -am 'Backport PR #47093: DOC/CI: Use more explicit data setup in user guides'
```

4. Push to a named branch:

```
git push YOURFORK 1.4.x:auto-backport-of-pr-47093-on-1.4.x
```

5. Create a PR against branch 1.4.x, I would have named this PR:

> "Backport PR #47093 on branch 1.4.x (DOC/CI: Use more explicit data setup in user guides)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the `Still Needs Manual Backport` label once the PR gets merged.

If these instructions are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                 @meeseeksdev backport 1.4.x Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

```
git checkout 1.4.x
git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
git cherry-pick -x -m1 339623b58abda42907f3090769d07c663e74a796
```

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

```
git commit -am 'Backport PR #47093: DOC/CI: Use more explicit data setup in user guides'
```

4. Push to a named branch:

```
git push YOURFORK 1.4.x:auto-backport-of-pr-47093-on-1.4.x
```

5. Create a PR against branch 1.4.x, I would have named this PR:

> "Backport PR #47093 on branch 1.4.x (DOC/CI: Use more explicit data setup in user guides)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the `Still Needs Manual Backport` label once the PR gets merged.

If these instructions are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                