feat: add polars_info function

[eitsupi]

Based on #262, close #269

Implement a function like arrow::arrow_info()

> polars_info()
R Polars package version: 0.6.1.9000

Features:          
simd FALSE

It provides fairly limited information for now, but other information can be added in the future.

[sorhawell]

good idea

the py-polars equivalent

>>> pl.show_versions()
--------Version info---------
Polars:      0.18.4
Index type:  UInt32
Platform:    macOS-12.6.6-x86_64-i386-64bit 
Python:      3.10.9 (main, Dec 15 2022, 18:18:30) [Clang 14.0.0 (clang-1400.0.29.202)]

----Optional dependencies---- 
numpy:       1.24.3
pandas:      <not installed>
pyarrow:     12.0.0
connectorx:  <not installed>
deltalake:   <not installed>
fsspec:      <not installed>
matplotlib:  <not installed>
xlsx2csv:    <not installed>
xlsxwriter:  <not installed>
>>> 

[etiennebacher]

LGTM, can you add a snapshot test?

[etiennebacher]

is it possible to have the rust-polars version as well? (and does it make sense to display it?)

[eitsupi]

Good point.
But we uses unreleased version of rust-polars here, so I think showing rust-polars' version make little sense.

[eitsupi]

Upon further investigation, it seems that there is no constant in rust-polars to display the version.
So I think we need to update rust-polars first to do that.

[eitsupi]

I have opened an issue about that. pola-rs/polars#9659

[eitsupi]

can you add a snapshot test?

I was hesitant to add a snapshot test, given that results can vary depending on build conditions.
But perhaps by forcing the values to be overwritten, only print results can be tested...

[etiennebacher]

Thank you @eitsupi

[eitsupi]

Sorry, I may have made a mistake on something.......
On the website after this PR is merged, simd shows FALSE as follows.
This should be TRUE.......

polars_info()
#> R Polars package version: 0.6.1.9000
#> 
#> Features:          
#> simd FALSE
#> 

[eitsupi]

Now I understand why. I had misunderstood the use of target_feature.
https://doc.rust-lang.org/reference/attributes/codegen.html#the-target_feature-attribute

I should use feature, not target_feature...