Limit the number of characters for the address field

[Xpirix]

We should limit the number of characters for the address, as it could overflow the organisation's certificate.
It is also possible to directly cut it when rendering the certificate:

[Xpirix]

Also, put QGIS Project Representative and add the Date of registration

[flyght7-admin]

Why not after certain characters use two lines for address? For legal reasons trimming the address may not be feasible.