invenio2-kickstart: customization for zenodo

* Specifies the name of the CFG_INVENIO2_REPOSITORY_GENERAL directory

* Checks for bower-base.json existence
We use `invenio-op` for zenodo (https://github.com/zenodo/invenio-op) as `CFG_INVENIO2_REPOSITORY_GENERAL`, so forcing the name here will solve the further problems with referencing to the `invenio`.