WIP: redirect Kwant 1.2.x tutorial URLs to Kwant 1.3.x ones

There's no way to test this except on the main website unfortunately.

This should not be merged until the main documentation points to the Kwant 1.3 docs (this will be built when the <1.3> tag is pushed)

I think that we may also have to manually put the htaccess file in the correct place. CI only does nikola deploy, and I don't think that this does anything with htaccess

I stand corrected -- nikola deploy will also copy the .htaccess over

added 5 commits

• 98b87d3f...81e37c67 - 4 commits from branch master
• 80e74b93 - redirect Kwant 1.2.x tutorial URLs to Kwant 1.3.x ones

Compare with previous version

merged