Project refactor home

[jochenklar]

This PR will add the new version of the home page.

[MyPyDavid]

I would like to split up the home template into several parts, so that it easier re-use and change only specific parts instead of copying the whole html file and make only few changes in there.
For example:

• home_header (it only includes the ones below)
  • home_header_images
  • home_header_text ( this can then also be _de and/or _en)
    I could add that in a separate PR targeting this branch.

I think some placeholders for institutional branding/funding logos would also be nice. What do you think about these type of logos on the bottom of https://about.coscine.de/? I'm not sure about the hover over text but there does need to be some description to each logo..

[jochenklar]

I think this should be done in the theme, and this is why home.html still exists. For "casual" rdmo users I think it is best to have one file (in each language) to edit.

[jochenklar]

I added home_header.html and home_login.html to hide things they do not need to change from those users.