2021-08-20: rewritten for CMK 2.0 by thl-cmk[at]outlook[dot]com
            based on the "BGP Peer State Check" check by Thomas Wollner (tw[at]ollner-net[dot]de),
            (http://wollner-net.de/check_mk/network_checks/bgp_peer-1.4.mkp)
2021-08-21: added more perfdata, added metrics file
2021-08-22: added WATO options, streamlined with cisco_bgp_peer
2021-08-29: moved static (longoutput) to inventory plugin
            moved helper functions to utils/bgp_peer
            WATO: removed htmloutput and infotext_values option
2021-11-14: merged check function with cisco_bgp_peer
            moved parse function to utils/bgp_peer
2022-04-02: WATO: added bgp neighbour states
            rewritten bgp neighbor state handling (made configurable)
2022-04-17: added peer_unavail_reason/peer_unavail_reason_str for huawei bgp peers            
2022-04-24: added peer status to inventory
            added option to remove some columns from inventory
2022-04-28: added whois information to inventory
2022-04-29: added upper/lower prefix limits from wato
            added info if device is admin prefix limit capable (device_admin_limit)
2022-04-30: code clenup
2022-05-02: fixed missing not_in_service_time from params
2022-05-09: made item name configurable (don't use address-family/routing-instance/VRF)
2022-05-11: changed bgp_get_peer_entry to get proper parameters instead of Nontransparent list
            added remote_as to BgpPeerItem
2022-05-12: merged bgp_get_ip_address_from_oid with bgp_render_ip_address
            changed IPv6 address format to lower case as required by rfc5952 section-4.3 (this affects IPv6 items)
2022-09-05: added missing wato parameters to register.check_plugin check_default_parameters
2022-09-05: added internal_item to WATO as hidden_key to avoid warnings on cmk updates (THX to Jay2k1 for reporting the issue)
2022-09-10: made more reliable on limited data (fsm_established_time and admin_state) (THX to martin[dot]pechstein[at]posteo[dot]de)
2022-09-11: optimized internal flow: > alias > not found > admin down > peer state > ...
2023-01-21: changed to always yield fsm_established_time (not only if beep connects, but also on all other states)
2023-01-20: add description to BgpPeerItem (for Arista)
2023-01-22: fix output for admin_state
2023-02-16: changed for CMK 2.1 (moved gui files from local/share/.. to local/lib/..)
            fix type error in discovery (CMK2.1 GUI only) 
2023-02-20: fix crash if metric data is None