Merge pull request #2744 in SNORT/snort3 from ~MIALTIZE/snort3:mpls to master

Merge pull request #2744 in SNORT/snort3 from ~MIALTIZE/snort3:mpls to master

Squashed commit of the following:

commit ee516377468dd17dfb4b1ff370d3912c96b29274
Author: Michael Altizer <mialtize@cisco.com>
Date:   Thu Feb 25 16:38:35 2021 -0500

    mpls: Add next layer autodetection and implement codec logging

    The max_mpls_stack_depth and mpls_payload_type parameters of the MPLS
    codec module have been renamed to max_stack_depth and payload_type
    respectively to cut down on redundancy.

    The EXP field in the MPLS header has been renamed to TC (traffic class)
    per RFC5462.  Previously available MPLS counters have been removed due
    to being both inaccurate and not very valuable.

commit c007bb268c0f94038e07646eb047f2f0659165a5
Author: Michael Altizer <mialtize@cisco.com>
Date:   Thu Feb 25 16:38:35 2021 -0500

    mpls: Refactor mpls.enable_mpls_overlapping_ip into packet.mpls_agnostic

commit c00686eb8b98ccca8ca61cbd3517733ffe64802a
Author: Michael Altizer <mialtize@cisco.com>
Date:   Thu Feb 25 16:38:35 2021 -0500

    mpls: Remove enable_mpls_multicast option

    The option was unused and MPLS multicast support is now always enabled.

commit 8b4edf540f2ac597e954b6edaace9e506d0d603a
Author: Michael Altizer <mialtize@cisco.com>
Date:   Thu Feb 25 16:38:35 2021 -0500

    loggers: Fix excessive byte reordering when printing MPLS labels in CSV and JSON

commit ec4488602cf3e45ed4b5f7385f7acd9099078205
Author: Michael Altizer <mialtize@cisco.com>
Date:   Thu Feb 25 16:38:35 2021 -0500

    trans_bridge: Lift the log() implementation from the root Ethernet codec