* Fix RKE2 MetalLB L2Advertisement to honor custom lb_pool_name (#135)
The apply-manifests role rendered the IPAddressPool from a template using
lb_pool_name, but applied the L2Advertisement from a hardcoded remote file
where the pool name was baked in as 'first-pool'. Setting lb_pool_name to
anything else left the L2Advertisement pointing at a non-existent pool, so
MetalLB assigned LoadBalancer IPs but never advertised them (services got an
external IP but were unreachable).
Template the L2Advertisement locally from lb_pool_name, mirroring the
IPAddressPool pattern, so both manifests always reference the same pool.
* Add explicit become: true to apply-manifests kubectl tasks
These tasks set become_user without a task-level become, tripping
ansible-lint's partial-become rule. become is already enabled globally via
ansible_become in group_vars/all.yaml, so the tasks already escalate to the
ansible user — but that is invisible to the linter (and to anyone reading the
task in isolation). Make it explicit with become: true alongside become_user.
Behavior-neutral: verified with ansible-playbook -vvv that the escalation
target is unchanged (sudo -u ansible; chown ansible on the temp files), so
kubectl still runs as the ansible user that owns ~/.kube/config.
