Allow annotating PDFs before signing them (#37, not final)

assets/dbp-official-signature-pdf-upload.metadata.json

assets/dbp-qualified-signature-pdf-upload.metadata.json

assets/dbp-signature.html.ejs

package.json

src/dbp-official-signature-pdf-upload.js

src/dbp-qualified-signature-pdf-upload.js

src/dbp-signature-lit-element.js

src/i18n/de/translation.json

src/i18n/en/translation.json

src/utils.js

yarn.lock