new block license

assets/sass/_theme/blocks/license.sass

assets/sass/_theme/hugo-osuny.sass

layouts/partials/blocks/templates/license.html

static/assets/images/blocks/license/by-nc-nd.svg

static/assets/images/blocks/license/by-nc-sa.svg

static/assets/images/blocks/license/by-nc.svg

static/assets/images/blocks/license/by-nd.svg

static/assets/images/blocks/license/by-sa.svg

static/assets/images/blocks/license/by.svg

static/assets/images/blocks/license/cc-zero.svg

static/assets/images/blocks/license/cc.srr.primary.svg

static/assets/images/blocks/license/publicdomain.svg