Schema generation needs to be updated to new Bisochemas website structure

[AlasdairGray]

The Bioschemas website has been restructured so that all versions of profiles and types are available. This has broken the generation script which reads various files from the website GitHub to generate the JSON-schemas used by the tool.

We'll also need to think about processing the files in the _data folder of the Bioschemas site so that we know which are releases and which are latest drafts.

[AlasdairGray]

@petrospaps I have updated the script. My code is available on the bioschemas-website-restructure branch.

Can you verify that the schemas generated with the new version of the script work with the tool?

We should also think about updating the tool so that it only generates new schemas or at least those generated in the _data/profile_versions.yaml file, not those of past profiles.

[AlasdairGray]

I have verified that the newly generated schemas work with the form generator and have now deployed the latest release or draft of each profile on the live deployment.

In doing this I have fixed #9 that was showing as errors in the generation process when a new type did not have an associated Bioschemas profile.

[AlasdairGray]

Fixed on branch ready to be merged in as PR #13