[bgp]: Update TSA functionality

[pavel-shirshov]

- Why I did it
Fixed TSA bugs:

1. TSA didn't advertise Loopback ipv6 address
2. TSA and TSB changed BGP dynamic and BGP monitors sessions

- How I did it

1. Use 'match ipv6 prefix-list' to match ipv6 loopback
2. Skip all route-maps, which doesn't have V4 or V6 in it. Both dynamic and monitors sessions doesn't have such suffixes because the sessions works for both ipv4 and ipv6. In the future it is better to re develop this feature inside of bgpcfgd.

- How to verify it
Build an image and run on your DUT.

admin@str-s6100-acs-1:~$ TSA
System Mode: Normal -> Maintenance
admin@str-s6100-acs-1:~$ vtysh -c 'show bgp ipv4 neighbors 10.0.0.1 advertised-routes'
BGP table version is 6, local router ID is 10.1.0.32, vrf id 0
Default local pref 100, local AS 64601
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 10.1.0.32/32     0.0.0.0                  0         32768 i

Total number of prefixes 1
admin@str-s6100-acs-1:~$ vtysh -c 'show bgp ipv6 neighbors fc00::a advertised-routes'
BGP table version is 6, local router ID is 10.1.0.32, vrf id 0
Default local pref 100, local AS 64601
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> fc00:1::/64      ::                       0         32768 i

Total number of prefixes 1
admin@str-s6100-acs-1:~$ TSB
System Mode: Maintenance -> Normal

- Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)