[Feature Request] Add functions to api

[D4rkw0lv3s]

Request Type

Feature Request

Work Environment

Question	Answer
OS version (server)	CentOS
OS version (client)	7
TheHive4py version / git hash	1.8.1

Problem Description

Be able to use /api/customField/_search, and have function like "find_custom_fields" and "update_custom_field"

Steps to Reproduce

/api/customField/_search - does not exists

Possible Solutions

add api call for the custom fields

Complementary information

[D4rkw0lv3s]

update_case(self, case, fields=[]) allow this.

Updatable fields are: [title, description, severity, startDate, owner, flag, tlp, pap, tags, status, resolutionStatus, impactStatus, summary, endDate, metrics, customFields]