MEDIUM: global: add the DeviceAtlas required elements to struct global

MEDIUM: global: add the DeviceAtlas required elements to struct global

This diff is the raw C struct definition of all DeviceAtlas module
data needed added to the main global struct haproxy configuration.
The three first members are needed for both init and deinit phases
as some dynamic memory allocations are done.
The useragentid serves to hold during the whole lifecycle of the
module the User-Agent HTTP Header identifier from the DeviceAtlas
data during the init process.