Add documentation, debugging

Utility for creating a new user account in postfixadmin, and setting account

values via Nextcloud.

## Usage

Send a `PUT` request to `example.com:9000/create-account`. Required parameters:

```

target_email

password

password_confirm

displayname

email_quota

fallback_email

nextcloud_quota

```

You can use the following command to make a request:

```

curl -X PUT https://example.com:9000/create-account \

    -d target_email=user@example.com -d password=pw -d password_confirm=pw \

    -d displayname=name -d email_quota=quota -d fallback_email=user@otherdomain.com \

    -d nextcloud_quota=-1

```

## Response values:

On success, status code will be 200 and response body:

```

'{"success": true}'

```

On failure, status code will be 4xx or 5xx and response body one of the following:

```

'{"success": false, "message": "username_forbidden"}'

'{"success": false, "message": "username_taken"}'

'{"success": false, "message": "internal_error"}'

```

class MyHandler(BaseHTTPRequestHandler):

    def do_PUT(self):

        if self.path == '/create-account':

        if self.path == '/create-account' or self.path == '/create-account/':

            # TODO: require a password

            length = int(self.headers['Content-Length'])

            postvars = urllib.parse.parse_qs(self.rfile.read(length))

            postvars = {k.decode(): v[0].decode() for k, v in postvars.items()}

            print(f'Received request PUT /create-account, parameters {postvars}')

            self.create_account(postvars['target_email'], postvars['password'], postvars['password_confirm'],

                                postvars['displayname'], postvars['email_quota'], postvars['fallback_email'],

                self.respond(403, data)

                return

            stdin, stdout, stderr = ssh.exec_command(

                f'/postfixadmin/scripts/postfixadmin-cli mailbox add "{target_email}" ' +

                f'--password "{password}" --password2 {password_confirm} --name "{displayname}" ' +

                f'--quota {email_quota} --active 1 --welcome-mail 0')

            command = f'/postfixadmin/scripts/postfixadmin-cli mailbox add "{target_email}" ' + \

                      f'--password "{password}" --password2 {password_confirm} --name "{displayname}" ' + \

                      f'--quota {email_quota} --active 1 --welcome-mail 0'

            print(f'command=command')

            stdin, stdout, stderr = ssh.exec_command(command)

            print(stdout.read())

            print(stderr.read())