build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/github.com/onsi/gomega/RELEASING.md

@@ -0,0 +1,23 @@
+A Gomega release is a tagged sha and a GitHub release.  To cut a release:
+
+1. Ensure CHANGELOG.md is up to date.
+  - Use 
+    ```bash
+    LAST_VERSION=$(git tag --sort=version:refname | tail -n1)
+    CHANGES=$(git log --pretty=format:'- %s [%h]' HEAD...$LAST_VERSION)
+    echo -e "## NEXT\n\n$CHANGES\n\n### Features\n\n### Fixes\n\n### Maintenance\n\n$(cat CHANGELOG.md)" > CHANGELOG.md
+    ```
+   to update the changelog
+  - Categorize the changes into
+    - Breaking Changes (requires a major version)
+    - New Features (minor version)
+    - Fixes (fix version)
+    - Maintenance (which in general should not be mentioned in `CHANGELOG.md` as they have no user impact)
+1. Update GOMEGA_VERSION in `gomega_dsl.go`
+1. Commit, push, and release:
+  ```
+  git commit -m "vM.m.p"
+  git push
+  gh release create "vM.m.p"
+  git fetch --tags origin master
+  ```