Delete unnecessary files and directories

[JeremyMcCormick]

I believe all of these could be deleted:

Dockerfile

assets/

data/

resources/

[gmantele]

I agree to remove:

• Dockerfile
• resources/

But please, do not remove yet the following:

• assets/ (I will use it when cleaning up the CSS stylesheet of the website)
• data/ (it may be useful for some special pages like the VO glossary, members, ...)