zebra: include route source set by route-map in show output

[mjstapp]

Include the prefix source address when set by a route-map in show output for routes, in various formats.
Add some debugs when encoding netlink route messages with a source address.

[riw777]

looks good

[riw777]

consistent ci failure here --

E AssertionError: 'r1' wrong number of route nexthops assert [1, 1, 1, 1, 2, 2, 3, 3, 3] == [1, 1, 1, 1, 2, 3, 3, 3, 3] At index 5 diff: 2 != 3 Full diff: - [1, 1, 1, 1, 2, 3, 3, 3, 3] ? --- + [1, 1, 1, 1, 2, 2, 3, 3, 3] ? +++

but only on debian (?) ... might need to be looked at?

[mjstapp]

thanks - I'll take a look...

consistent ci failure here --

E AssertionError: 'r1' wrong number of route nexthops assert [1, 1, 1, 1, 2, 2, 3, 3, 3] == [1, 1, 1, 1, 2, 3, 3, 3, 3] At index 5 diff: 2 != 3 Full diff: - [1, 1, 1, 1, 2, 3, 3, 3, 3] ? --- + [1, 1, 1, 1, 2, 2, 3, 3, 3] ? +++

but only on debian (?) ... might need to be looked at?