Merge pull request #2174 in SNORT/snort3 from ~AGIURGIU/snort3:appid_http2_ms_detect...

Merge pull request #2174 in SNORT/snort3 from ~AGIURGIU/snort3:appid_http2_ms_detect to master

Squashed commit of the following:

commit 3b0b9e7dbc443903f9f19def32648bc57bafb4da
Author: Shravan Rangaraju <shrarang@cisco.com>
Date:   Thu Apr 30 01:23:44 2020 -0400

    appid: support for multi-stream http2 session

commit c55b5718ef6877bbf16f4d1a3fde16f16117a2d3
Author: Shravan Rangaraju <shrarang@cisco.com>
Date:   Thu Apr 23 02:27:23 2020 -0400

    appid: store appids for http traffic in http session

commit 8a78d00add4080c77538196d0ae98ffa74db1dfa
Author: Kanimozhi Murthi <kamurthi@cisco.com>
Date:   Tue Apr 7 23:43:51 2020 -0400

    appid: remove old http2 support