vAccel versioning design

[olagkasn]

In order to facilitate vAccel building and intergration with other projects (e.g kata-containers) through CI/CD techniques we have to design a way to keep track of the compatible versions between different vAccel components.

One example is the following:
In order to build the kata kernel we also need to build the virtio-accel module against it. This module needs to be in sync with the rest of the vAccel components (vaccelrt, plugins) that will be used in the final kata-vaccel deployment.

There are and there will be more examples like this, so Versioning is something we should take seriously into account.

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One way to do that is to use branches or tags with the same name across the different components and submodules and keep this information in a VERSION.yaml file in the parent repo of vaccel.

Each tag or ""stable"" release will have the same tag accross all the submodules
e.g In the vaccel release-X branch repo (or release-X tag) each submodule should point respectively to the release-X branch module's repo (or release-X tag).

We can do this at first for one testing branch and one "stable" branch. Every new dev branch will then be tested and when it's ready it will be tagged as testing (with all its submodules). At the end the testing tag will be a new "stable" branch.

PS: the words "testing", "release", "stable" can be overwritten by someting else for now