Merge pull request #1272 in SNORT/snort3 from appid_httpMetaArray to master

Merge pull request #1272 in SNORT/snort3 from appid_httpMetaArray to master

Squashed commit of the following:

commit 8cf36b098955d12fed86df29ff29c654be8249f9
Author: Silviu Minut <sminut@cisco.com>
Date:   Wed Jun 13 18:33:15 2018 -0400

    appid: consolidate http metadata by removing the string pointers and keeping an array of pointers and offsets.

    appid: add convenience get_cfield function returning a char* rather than string*

    appid: add back get_xff_addr(), which was mistakenly removed.

    appid: use the convenince get_cfield function

    appid: code clean-up

    appid: reduce the size of the meta_offset array and add comments to the HttpFieldIds enum.

    appid: nit pick fixes and temporary static friend function inside the AppIdHttpSession class.

    appid: revert the static friend experiment and make the meta_offset array protected in AppIdHttpSession, with public set/get functions.

    appid: uncrustify

    appid: provide separate get/set functions for offsets, do away with MAX_PATTERN_TYPE and rename MAX_HTTP_FIELD_ID to NUM_HTTP_FIELDS

    appid: uncrustify appid_http_session.h

commit ef1aedfc90c2e25db192f5ead615f9d36f6c9757
Author: Silviu Minut <sminut@cisco.com>
Date:   Fri Jun 8 23:04:48 2018 -0400

    appid: remove http_fields array from AppIdHttpSession

    appid: consolidate http metadata in appid by removing the http_fields array from http session. Needs clean-up.

    appid: code clean-up for removing duplicate http metadata and unit test fix.

    appid: clean-up after rebase to master

    appid: remove commented out http_fields array

    appid: do not delete metadata string pointers in AppIdHttpSession::process_http_packet