feat(utils) new get_body_info() public API (#2822)
feat(utils) new get_body_info() public API (#2822)

New public API `get_body_info()` to retrieve:
- parsed body args (similar to `get_body_args()` (table)
- error code due to potential unknown request MIME type
- raw body (string)
- the request MIME type (as an enum value for programmable usage)

New public API enum values:
- `req_mime_types`: table containing known request MIME types
- `req_body_errors`: table containing enum of req body parsing errors

The previous `get_body_args()` API is left untouched from a user's POV
to preserve backwards compatibility: it still return only one argument
which is the parsed body, or an empty table.

The implementation tries to be efficient and lazily reads the request
body only when necessary.
jebenexer/kong,Kong/kong,salazar/kong,Kong/kong,icyxp/kong,Mashape/kong,Kong/kong