http: target parsing improvement

http: target parsing improvement

Make it http version neutral, since h2 and h3 use 3 pseudo-headers.
Added scheme, target_authority_offset and target_authority_len
to http_msg_data_t, target_form removed.
Http transport now validate if correct form of request target
is received, so now we are also able to receive requests with
absolute-form target in server apps like http_static.
As bonus, unformat is not longer used to parse IP addresses.

Type: improvement

Change-Id: I369f77e2639c43cc1244d91f883c526eb88af63e
Signed-off-by: Matus Fabian <[email protected]>