Harmonize (strip away Type) *Type models

ref: https://github.com/dandi/dandischema/pull/6/files#r639128369 saying

I am somewhat at loss of when `Type` suffix is used or not

Here are the ones without `Type` suffix

```shell
$> git grep 'class .*(' dandischema/models.py | grep -v 'Type('
dandischema/models.py:class HandleKeyEnumEncoder(json.JSONEncoder):
dandischema/models.py:class DandiBaseModelMeta(ModelMetaclass):
dandischema/models.py:class DandiBaseModel(BaseModel, metaclass=DandiBaseModelMeta):
dandischema/models.py:class PropertyValue(DandiBaseModel):
dandischema/models.py:class Anatomy(BaseType):
dandischema/models.py:class Disorder(BaseType):
dandischema/models.py:class ContactPoint(DandiBaseModel):
dandischema/models.py:class Contributor(DandiBaseModel):
dandischema/models.py:class Organization(Contributor):
dandischema/models.py:class Person(Contributor):
dandischema/models.py:class Software(DandiBaseModel):
dandischema/models.py:class Agent(DandiBaseModel):
dandischema/models.py:class EthicsApproval(DandiBaseModel):
dandischema/models.py:class Resource(DandiBaseModel):
dandischema/models.py:class AccessRequirements(DandiBaseModel):
dandischema/models.py:class AssetsSummary(DandiBaseModel):
dandischema/models.py:class Equipment(DandiBaseModel):
dandischema/models.py:class Activity(DandiBaseModel):
dandischema/models.py:class Project(Activity):
dandischema/models.py:class Session(Activity):
dandischema/models.py:class PublishActivity(Activity):
dandischema/models.py:class Locus(DandiBaseModel):
dandischema/models.py:class Allele(DandiBaseModel):
dandischema/models.py:class GenotypeInfo(DandiBaseModel):
dandischema/models.py:class RelatedParticipant(DandiBaseModel):
dandischema/models.py:class Participant(DandiBaseModel):
dandischema/models.py:class BioSample(DandiBaseModel):
dandischema/models.py:class CommonModel(DandiBaseModel):
dandischema/models.py:class Dandiset(CommonModel):
dandischema/models.py:class BareAsset(CommonModel):
dandischema/models.py:class Asset(BareAsset):
dandischema/models.py:class Publishable(DandiBaseModel):
dandischema/models.py:class PublishedDandiset(Dandiset, Publishable):
dandischema/models.py:class PublishedAsset(Asset, Publishable):
```

so from looks of it, if `Type` is desired for subclasses of `BaseType` then it is only
```
dandischema/models.py:class Anatomy(BaseType):
dandischema/models.py:class Disorder(BaseType):
```
which should be tuned up. But what is the rationale/benefit from keeping `Type` suffix altogether? It seems that `BaseType` is just an Enum-based `DandiBaseModel`. So they all could just be as happy without `Type` suffix and thus become consistent (I do not see a value from somehow annotating with Type that it is Enum based... what if some would be relaxed and no longer Enum based?)