Database name, admin, and type

[brimoor]

This PR adds some useful utilities for configuring database access.

Database name

A new database_name config setting is added that allows for users to customize their MongoDB database name:

import fiftyone as fo

print(fo.list_datasets())  # [...]
print(fo.config.database_name)  # fiftyone

export FIFTYONE_DATABASE_NAME=fiftytwo

import fiftyone as fo
import fiftyone.core.odm as foo

print(fo.list_datasets())  # []
print(fo.config.database_name)  # fiftytwo

foo.drop_database()  # cleanup

unset FIFTYONE_DATABASE_NAME

Database/client types

Notions of database type and client type are added, and now database connections are refused if a Python client's type does not match the database's type.

The client type is hard-coded in fiftyone.constants.CLIENT_TYPE, and the database's type is stored in a new type field of the config collection.

This is an internal mechanism that exists to prevent OSS Python clients from connecting to non-OSS databases.

Database admin

A new database_admin config setting is added. This parameter defaults to True, but clients can set it to False, in which case database migrations are not allowed (other than lazily migrating a dataset to the current database version, which is normal usage):

fiftyone migrate -v 0.15.0.1
export FIFTYONE_DATABASE_ADMIN=false

import fiftyone as fo  # ERROR: only admins can migrate

unset FIFTYONE_DATABASE_ADMIN

import fiftyone as fo
# Migrating database to v0.15.1

The documentation explains how this feature may be useful for OSS users leveraging database_uri to work on a shared database:

[j053y]

LGTM