chore: Optimize the Dockerfile to reduce the image size

[Kinsue]

This PR aims to address the issue raised in #615 by optimizing the final image size through merging build layers and removing related caches.

[Kinsue]

Current size

REPOSITORY         TAG       IMAGE ID       CREATED        SIZE
apisix/rearrange   redhat    0b09a77bc27b   13 hours ago   470MB
apisix/rearrange   ubuntu    32f780e9a8fd   17 hours ago   309MB
apisix/rearrange   debian    4011be1b9bf1   20 hours ago   315MB

Original size

REPOSITORY         TAG                IMAGE ID       CREATED        SIZE
apache/apisix    3.15.0-redhat      e5c331b94925   4 weeks ago     645MB
apache/apisix    3.15.0-ubuntu      57f35b524d54   4 weeks ago     458MB
apache/apisix    3.15.0-debian      1dd988645791   4 weeks ago     407MB

[github-actions]

This pull request has been marked as stale due to 60 days of inactivity. It will be closed in 4 weeks if no further activity occurs. If you think that's incorrect or this pull request should instead be reviewed, please simply write any comment. Even if closed, you can still revive the PR at any time ordiscuss it on the dev@apisix.apache.org list. Thank you for your contributions.

[shreemaan-abhishek]

@Kinsue please fix the failing CI and resolve conflicts with master.

[Kinsue]

@shreemaan-abhishek OK, I will handle this over the weekend.

[github-actions]

This pull request has been marked as stale due to 60 days of inactivity. It will be closed in 4 weeks if no further activity occurs. If you think that's incorrect or this pull request should instead be reviewed, please simply write any comment. Even if closed, you can still revive the PR at any time ordiscuss it on the dev@apisix.apache.org list. Thank you for your contributions.