Add new terms an hierarchy for microbiota

[ramonawalls]

See also #70, EnvironmentOntology/envo#807, and OHMI-ontology/OHMI#2.

Following an in person discussion with @zhengj2007 and @yongqunh, we decided to keep the current term for microbial community, but to add some other microbioata classes for other use cases, in the hierarchy below:

• collection of organisms
  -- collection of microbial organisms
  --- multi-species collection of microbes
  ---- microbial community
  --- single species collection of microbes
  -- multi-species collection of organisms
  --- ecological community
  ---- microbial community
  --- multi-species collection of microbes
  ---- microbial community
  -- single-species collection of organisms
  --- population of organisms
  ---- microbial population

This is a complex hierarchy, so I will make a PR soon for people to review, and to make sure I got it right.

New terms:

collection of microbial organisms: A collection of organisms consisting of two or more microbes.
exact synonym: microbiota

multi-species collection of microbes: A multi-species collection of organisms that consists of two or more microbes from at least two species.

single species collection of microbes: A single-species collection of organisms that consists of two or more microbes of the same species and no members of any other species.

microbial population: A population of organisms consisting of only microbes of the same species, that live in the same place.
broad synonym: microbiota

For reference, the existing term is:
microbial community: An ecological community which is composed of co-existing populations of microbes that interact, directly or indirectly, such that they impact one another's ecological fitness.
Add broad synonym: microbiota

[ramonawalls]

@zhengj2007 and @yongqunh I added these classes to pco-edit.owl. Do you want to check them before I do a release?

[zhengj2007]

@ramonawalls I trust you and would like you to go ahead and make the release.

[yongqunh]

@ramonawalls yes. please go ahead to release the terms. We will later then import these terms to OHMI. Thanks.

[ramonawalls]

Thanks @zhengj2007 and @yongqunh. I'll let you know when the new release is done.

[zhengj2007]

Thanks @ramonawalls

[ramonawalls]

The release is out. I made a typo in the version IRI, so it say 2020-02-13 instead of 2020-02-12, but I don't think that will affect anything important, so I am going to leave it, and tomorrow it will be the 13th!