Adding new types of exposure classification

[diatomsRcool]

@matentzn As we discussed in our meeting last Thurs:
These are the higher-level classes I would like to add to ECTO

1. occupational exposure
2. passive exposure
3. active exposure
4. prenatal exposure
5. dietary exposure
6. experimental exposure
7. exposure via ingestion
8. exposure via inhalation
9. exposure via injection
10. exposure via absorption

[matentzn]

Done - see the linked PR. How each was modelled:

Route group - new exposure_by_route pattern, logically defined as 'exposure event' and ('has exposure route' some <route>), so existing exposure to X via <route> terms classify underneath automatically:

• exposure via ingestion (ECTO:0110001)
• exposure via inhalation (ECTO:0110002)
• exposure via injection (ECTO:0110003)
• exposure via absorption (ECTO:0110004)

Manner/context group - there's no relation in ECTO/ExO/RO to define these logically (voluntary vs involuntary, at-work, in-an-experiment, before-birth), so they go in as primitive subclasses of exposure event. Happy to revisit if we want to model intent/context properly:

• occupational exposure (ECTO:0000981)
• passive exposure (ECTO:0000982)
• active exposure (ECTO:0000983)
• prenatal exposure (ECTO:0000984)
• dietary exposure (ECTO:0000985)
• experimental exposure (ECTO:0000986)

prenatal exposure could instead be defined via the maternal route (ExO:0000159); I left it primitive for now since maternal-route isn't quite the same as prenatal timing - shout if you'd prefer the logical definition.

While in here I also added a few grouping classes to tidy up the terms dangling directly under exposure event (fish, maternal route, consumption behaviour, a GO-based exposure to behavioural process above the NCIT-based exposure to behavior, and radiation) - details in the PR.