[Modules] Enhancing extra specifiers

[Xavier D. <xav...@gm...>]

Dear All,

"tag" extra specifier is added to search modules based on tags that
apply to them. Moreover, multiple names can now be specified on one
extra specifier criterion to select modules matching any of these
names.

Details and example are available at:

https://modules.readthedocs.io/en/latest/MIGRATING.html#enhancing-extra-specifiers

Regards,
Xavier