add version parser to aiida core utils

[ltalirz]

This piece of code to parse the aiida version will be useful for any plugin that supports both aiida 0.12 and 1.0.

https://github.com/aiida-vasp/aiida-vasp/blob/268e2a41c96d8fda229937dd3c6f828853acb503/aiida_vasp/utils/aiida_utils.py#L127-L133

I suggest to add this in aiida/utils, both in release_0.12.3 and in develop

@giovannipizzi @sphuber Do you agree?

[ltalirz]

Ok, I think this is already sufficiently covered by aiida.get_strict_version()

[ltalirz]

Actually, this function is missing from the release_v0.12.3 branch.
I will add it.

[sphuber]

Fixed in release_v0.12.3 in PR #2099