[CI] Add container image build ci

[Yikun]

What this PR does / why we need it?

Add container image build ci:

• Enable branch, tag docker image publish
  • branch image: vllm-ascend:main, vllm-ascend:v0.7.1-dev
  • tag image: vllm-ascend:v0.7.1rc1
• Enable PR docker image build check
• other changes:
  • Prepare the REPO_OWNER because the ghcr lowerercase required
  • Add Free up disk space step to avoid No space left on device like 有直接可用的容器镜像吗？ #27
  • Setup qemu with image to resolve tonistiigi/binfmt:latest (qemu 9.2.0) segfault on ubuntu-24.04 / ubuntu-latest docker/setup-qemu-action#198

Does this PR introduce any user-facing change?

NO

How was this patch tested?

build: CI passed push false
Note for test case:

1. merge commits ot main, v0.7.1-dev branch
   ✅ main: https://github.com/Yikun/vllm-ascend/actions/runs/13347238961 --> ghcr.io/yikun/vllm-ascend:main OK
   ✅v0.7.1-dev: https://github.com/Yikun/vllm-ascend/actions/runs/13347229912 --> ghcr.io/yikun/vllm-ascend:v0.7.1-dev OK

2. create pep440 tag from github release: v0.7.1rc1, v0.7.1, v0.7.1rc1.dev1 all release has latest
   ✅ v0.7.5 --> v0.7.5, latest
   ✅ v0.7.5rc1 --> v0.7.5rc1
   ✅ v0.7.5rc1.dev1 --> v0.7.5rc1.dev1
   (no latest, add a todo here) v0.7.5rc1.post1 --> v0.7.5rc1.post1

3. create unknow tag from github release:
   ✅ create 0.7.1 on v0.7.1-dev: not trigger ( only prefix v triggerd)

4. create tag from git:
   ✅ also works, git tag v0.7.99;git push origin v0.7.99 from publish-image

[wangxiyuan]

image build will work even a pull_request is created?

[Yikun]

yes, only build check without push, see the ci results in current PR.

push: ${{ github.event_name != 'pull_request' }}

otherwise, we can guarantee the docker quality, but need 30 mins to check.

the whole workflow is

1. first PR check
2. then auto publish branch dev image for each commits
3. auto publish final image when tag

[Yikun]

yes, only build check without push, see the ci results in current PR.

push: ${{ github.event_name != 'pull_request' }}

otherwise, we can guarantee the docker quality, but need 30 mins to check.

the whole workflow is

1. first PR check
2. then auto publish branch dev image for each commits
3. auto publish final image when tag

[Yikun]

I think it's ready to go, after this PR merged:

1. ghcr.io/vllm-project/vllm-ascend:main will be published
2. main branch image build check will be enable
3. the PR should be backported to v0.7.1-dev branch (with 0.7.1 dockerfile)

[Yikun]

Let's monitor the results:

1. ghcr.io/vllm-project/vllm-ascend:main: https://github.com/vllm-project/vllm-ascend/actions/runs/13360736837/job/37309987189
2. OK
3. v0.7.1-dev PR: [v0.7.1][CI] Add container image build ci #65