Local import and remove HAVE_PACKAGE logic

[samuelgarcia]

This PR remove unnecessary import at module level and import extra dependency only when they are needed when instanciating an IO class.

See #1160

This should:

• help in complicated environement (by not importing everything)
• decrease import duration

The drawback:

• it raise error only when instanciate (run time) and not at load time.

[samuelgarcia]

@alejoe91

[pep8speaks]

Hello @samuelgarcia! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2022-08-31 06:50:56 UTC

[JuliaSprenger]

Hi @samuelgarcia
Thanks for the simplifications. Did you confirm this is reducing the import time?
I think we are loosing at tiny bit of user friendliness here, but it also simplifies the code, so let's go with it.

[JuliaSprenger]

For reference: This change improves the import time on my system from 1.6s to 0.5s. @samuelgarcia It works 👍

[samuelgarcia]

cool.
To be totaly honest I did not make benchmark :)