results: allow assigning environment to results in result configuration

results: allow assigning environment to results in result configuration

This is done by assigning a dictionary to the 'env' attribute
of a result configuration.
The environment configured this way is merged into the environment
and overrides variables from the project wide configuration files.

BuildId is handled by merging these variables into the result
specific environment before BuildId calculation.

Signed-off-by: Gordon Hecker <gh@emlix.com>