Feature/clea qrcode simulator

Component that generate Cléa QR code (static or dynamic).
The Generator features a builder that enables creating a QR generator for a specific Location, with their secret key, venue type, categories and other location specific data. One should also provide public key for the MCTA and Server Authority. Once the generator created, we can call generateAt() to generate a QR code for a timestamp during the current period or startNewPeriod() to start a new period.
The generator takes care of generating those QR code at the valid timestamp, and not re-generating one if it already exists for the provided timestamp, according to qrRenewalInterval and period.