Fix: Cleanup BIRD VRF config (part 1)

[ipspace]

• Create a common per-VRF tagging filter that replaces the per-proto tagging code
• Add VRF name to VRF routes (that will make inter-VRF route leaking easier)
• Convert import/export RTs to BIRD syntax in device quirk and use the BIRD-formatted values in Jinja2 templates

[Copilot]

Pull request overview

This PR refactors BIRD VRF configuration generation by centralizing VRF route tagging into a common per-VRF filter, introducing BIRD-formatted import/export route-target tuples produced by a device quirk, and embedding VRF identity into VRF-learned routes to support inter-VRF leaking workflows.

Changes:

• Add bird_vrf_rt() device quirk to precompute per-VRF _bird_import / _bird_export route-target tuples for use in templates.
• Introduce per-VRF vrf_<name>_tag filter and netlab_vrf_name attribute, and switch multiple protocols/macros to use the shared filter instead of inline tagging code.
• Update inter-VRF leaking logic to compare and emit BIRD-formatted route-target tuples.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
netsim/devices/bird.py	Adds a quirk to convert VRF import/export RT strings into BIRD tuple syntax for templates.
netsim/daemons/bird/vrf-daemon.j2	Adds netlab_vrf_name and a shared per-VRF tag filter; updates tagging and VRF leaking to use _bird_* RT values.
netsim/daemons/bird/ospf.macros.j2	Switches VRF OSPF protocol instances to use the shared vrf_<name>_tag import filter.
netsim/daemons/bird/bgp.macros.j2	Switches VRF BGP protocol instances to use the shared vrf_<name>_tag import filter.