Submodule specgen_common_assets and treat as source of truth

[opoudjis]

Follows from #34

Once the specgen_common_assets repository is created, the batch file to execute specgen needs to start by:

• updating the local copy (submodule) of specgen_common_assets
• copying the files from specgen_common_assets into the right place for specgen to use them

So do the following:

• Get the git address of your new repository, from the Code button on its home page:

It will be something like https://github.com/Access4LearningNA/specgen_common_assets.git

• Go to your CLI tool and navigate to your copy of specgen_input_na
• Issue the command git submodule add https://github.com/Access4LearningNA/specgen_common_assets.git specgen_common_assets. This will schedule Github to create a folder called specgen_common_assets, which will contain the contents of that repo.
• Issue the command git submodule update --init --recursive. That will download the contents of the repo into that folder
• In your batch file to generate the spec, add at the start the command git submodule update --remote --merge. This updates the contents of all your submodule folders to the latest content from their source repos
• In your batch file, add the command cp specgen_common_assets/*.* 98_xslt, or equivalent, to copy all content across from the folder into the sourcetree of specgen_input. You can elect to remove the corresponding files under 98_xslt in specgen_input, since the source of truth for those files is now specgen_common_assets, and they are just copied across to 98_xslt

Refer https://devconnected.com/how-to-add-and-update-git-submodules/

[opoudjis]

I've finished work on this my side. @4pins feel free to look at what I've done to compare notes.