Add "Search using search request" - POST method

[tess1o]

Please consider implementation of "Search using search request" with POST method. It allows to avoid GET requests limitations (for instance the length of GET url).

Atlassian documentation - https://docs.atlassian.com/software/jira/docs/api/REST/8.4.2/#api/2/search-searchUsingSearchRequest

API: POST /rest/api/2/search
Request body example:

{
    "jql": "project = HSP",
    "startAt": 0,
    "maxResults": 15,
    "fields": [
        "summary",
        "status",
        "assignee"
    ]
}

Response example:

{
    "expand": "names,schema",
    "startAt": 0,
    "maxResults": 50,
    "total": 1,
    "issues": [
        {
            "expand": "",
            "id": "10001",
            "self": "http://www.example.com/jira/rest/api/2/issue/10001",
            "key": "HSP-1"
        }
    ]
}

[tess1o]

There is a PR that implements this API - #461

I will close this ticket, hope it can be merged