Fix misspellings found with codespell across headers, sources, examples,
tests and the documentation, including "propably" in the nodeset
compiler docs. Identifiers, companion spec names and generated code are
left untouched.
This commit drops the 'ua_' prefix and changes the public includes
to the form `#include <open62541/server.h>` instead of the old
`#include <ua_server.h>`
Make use of EXIT_SUCCESS and EXIT_FAILURE from stdlib.h.
The previous approach of returning a value from UA_StatusCode
was often broken as an exit code can (portably) only be between 0 and 125.
Andreas Ebner