Add support for emoji-data.txt and emoji-variation-sequences.txt to unicodedata

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-08-23.20:34:50.618>
labels = ['3.10', 'type-feature', '3.9', 'expert-unicode']
title = 'Add support for emoji-data.txt and emoji-variation-sequences.txt to unicodedata'
updated_at = <Date 2020-09-01.09:46:27.836>
user = 'https://github.com/jack1142'

bugs.python.org fields:

activity = <Date 2020-09-01.09:46:27.836>
actor = 'vstinner'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Unicode']
creation = <Date 2020-08-23.20:34:50.618>
creator = 'jack1142'
dependencies = []
files = []
hgrepos = []
issue_num = 41622
keywords = []
message_count = 2.0
messages = ['375826', '376084']
nosy_count = 3.0
nosy_names = ['terry.reedy', 'ezio.melotti', 'jack1142']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue41622'
versions = ['Python 3.9', 'Python 3.10']