Remove theme from gitignore & add .html to imports

.gitignore

theme/templates/404.html.nunj

theme/templates/article.html.nunj

theme/templates/gallery.html.nunjucks

theme/templates/partials/footer.html.nunj

theme/templates/partials/header.html.nunj

theme/templates/partials/list.html.nunj

theme/templates/partials/paginator.html.nunj

theme/templates/partials/search.html.nunj

theme/templates/partials/svgs.html.nunj

theme/templates/redirect.html.nunj

theme/templates/tag.html.nunj

theme/templates/tag.html.nunjucks