Add progress bar for visualizing the computation

In order to give a visual feedback when a lengthy metric computation has
been issued I have added progress bars to each metric. I had to adjust
the stylesheets a bit.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Add missing argument for completeness worker

There was a missing argument, as well as as a missing call to self.class
for symbolize_keys which prevented the completeness metric from working.
This commit fixes that.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Add and activate sidekiq-status plugin

In order to fetch information of the process of the worker's job I have
added a sidekiq plugin dedicated for this task.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Provide worker's job progress information

I am now providing the worker's job progress as a JSON object on the
route /metrics/status. For now I am using a class variable to store the
job id information across requests. However, in the future I am going to
store these data in the database.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Implement repetitive check progress AJAX requests

I have added a function which triggers repetitive AJAX requests until
all jobs are finished. Currently, the function is not triggered if a
computation job is started, but for now the basic visualization works.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>