##### SUMMARY
hall module:  the hall.com is not available
```
 19 description:
 20     - "The C(hall) module connects to the U(https://hall.com) messaging API and allows you to deliver notication messages to rooms."
...
 24   room_token:
 25     description:
 26       - "Room token provided to you by setting up the Ansible room integation on U(https://hall.com)"
...
 65 HALL_API_ENDPOINT = 'https://hall.com/api/1/services/generic/%s'
```
It looks like https://hall.com is not available
```
test:~$ ping hall.com
ping: hall.com: No address associated with hostname
test:~$ ping www.hall.com
ping: www.hall.com: Name or service not known
test:~$ host hall.com
hall.com mail is handled by 10 mxa.mailgun.org.
hall.com mail is handled by 20 mxb.mailgun.org.
test:~$ host www.hall.com
Host www.hall.com not found: 3(NXDOMAIN)
```
I can't find any information about this service exists nowadays or not

Therefore, the module must be removed or fixed.

##### ISSUE TYPE
- Documentation Report

##### COMPONENT NAME
```lib/ansible/modules/notification/hall.py```

##### ANSIBLE VERSION
```
2.8
```
from __future__ import absolute_import, division, print_function
__metaclass__ = type
ANSIBLE_METADATA = {'metadata_version': '1.1',
                    'status': ['preview'],
                    'supported_by': 'community'}
DOCUMENTATION = """
module: hall
short_description: Send notification to Hall
description:
    - "The C(hall) module connects to the U(https://hall.com) messaging API and allows you to deliver notication messages to rooms."
version_added: "2.0"
author: Billy Kimble (@bkimble) <basslines@gmail.com>
options:
  room_token:
    description:
      - "Room token provided to you by setting up the Ansible room integation on U(https://hall.com)"
    required: true
  msg:
    description:
      - The message you wish to deliver as a notification
    required: true
  title: