gh-37231: Use matroid-database package
Remove matroid database files (`ext_data/matroids`) and use newly
created `matroid-database` pypi package instead.
Links to `matroid-database`: [pypi](https://pypi.org/project/matroid-
database/), [github](https://github.com/gmou3/matroid-database)
Outdated:
> Compress (via `xz -e`) the matroid database files (~75MB to <1MB). The
files are now opened with `lzma.open()` and the file paths are located
through `sage.ext_data` and not relative to `SAGE_SRC` or
`SAGE_EXTCODE`. These changes attempt to address the issues raised by
@tornaria.
>
> Also, the addition of the matroid database files inside the folder
`ext_data` needs to be noted in the file `setup.cfg.m4`. This issue was
brought to my attention by @antonio-rojas.
>
> These follow the merging of #37140.
>
> I also took the initiative of reordering alphabetically the list of
paths inside `setup.cfg.m4` and of removing the line `ext_data/images/*`
which seemed redundant.
<!-- Why is this change required? What problem does it solve? -->
<!-- If this PR resolves an open issue, please link to it here. For
example "Fixes #12345". -->
<!-- If your change requires a documentation PR, please link it
appropriately. -->
### :memo: Checklist
- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion.
URL: https://github.com/sagemath/sage/pull/37231
Reported by: gmou3
Reviewer(s): gmou3, Gonzalo Tornaría, Matthias Köppe
