Rename the repository to inbuxa-webmail

The repository moved from inbuxa/ihasmail-inbuxa to inbuxa/inbuxa-webmail,
matching inbuxa-server and inbuxa-admin. Point the source links, the image
name and the package link at the new name. The OAuth client id stays
ihasmail-inbuxa, since that is what the server registers.

.gitea/workflows/ci.yml

@@ -133,7 +133,7 @@ jobs:
           echo "DOCKER_TAG=${V/+/-}" >> "$GITHUB_OUTPUT"
           echo "VERSION=$V DOCKER_TAG=${V/+/-}"
 
-  # Multi-arch image at <REGISTRY>/inbuxa/ihasmail-inbuxa, then the release.
+  # Multi-arch image at <REGISTRY>/inbuxa/inbuxa-webmail, then the release.
   # arm64 is built under QEMU on this amd64 host, which is slow but fine for
   # a hand-cut release. PACKAGE_TOKEN (jcoffey-dev, write:package) logs in:
   # the job's own token is refused by the container registry. The release is