Ability to disable git submodules adding to the giterminism context

[distorhead]

Before proceeding

• I didn't find a similar issue

Problem

There are submodules in the git repo, which should not be added into the built images, and no files from submodules used in werf.yaml or .helm configuration files.

Solution (if you have one)

So in such case we could optimize git archive fetch procedure and disable fetching submodules.

Additional information

No response