Simplify the Docker image tag and disable releases to DDN for now. (#88)

### What

This removes the timestamp from the Docker image tag.

Docker images are inherently timestamped so we do not need this.

We also disable releases to DDN until we have moved over to the new
image location.

### How

Deleting code, mostly.

ci/deploy.sh

@@ -44,28 +44,22 @@ function run {
 # Assumes that the given ref is a branch name. Sets a tag for a docker image of
 # the form:
 #
-#                dev-main-20230601T1933-bffd555
-#                --- ---- ------------- -------
-#                ↑   ↑         ↑           ↑
-#     prefix "dev"   branch    |        commit hash
-#                              |
-#                    commit date & time (UTC)
+#                dev-main-bffd555
+#                --- ---- -------
+#                ↑   ↑       ↑
+#     prefix "dev"   |      commit hash
+#                  branch
 #
 # Additionally sets a branch tag assuming this is the latest tag for the given
 # branch. The branch tag has the form: dev-main
 function set_dev_tags {
     local branch="$1"
-    # replace '/' in branch name with '-'
+    # replace '.' and '/' in branch name with '-'
     local tidy_branch
-    tidy_branch="$(echo "${branch}" | tr "//" -)"
-    local branch_prefix="dev-$tidy_branch"
+    tidy_branch="$(tr './' '-' <<< "$branch")"
+    local branch_prefix="dev-${tidy_branch}"
     local version
-    version=$(
-        TZ=UTC0 git show \
-            --quiet \
-            --date='format-local:%Y%m%dT%H%M' \
-            --format="$branch_prefix-%cd-%h"
-    )
+    version=$(git show --quiet --format="${branch_prefix}-%h")
     export docker_tags=("$version" "$branch_prefix")
 }