Facing Belfast’s City Hall on historic Donegall Square, the Scottish Provident building is an eye-catching landmark. The ornate façade of the Victorian commercial edifice hides more architectural surprises inside, where stained windows and original decorative tiles line the stairways and corridors. As we sit down in one of the office suites that serves as the head office of Cloudsmith, the company’s co-founder and chief strategy officer Alan Carson tells me he first set foot in this building at the age of eight, on days when he met his father at work. Now he is 47 and a vivid blue neon…