Add option to set report title in cmd mode

[mbanck]

This adds an additional command-line option -cmd-title which allows to
overwrite the default title (i.e. dashboard name). Depending on the dashboard
naming scheme, or the particular time-range of the report, the user might want
to set a custom title (like `Daily report for...') without having to use custom
templates.

[IzakMarais]

Thanks for this. It looks like it is also available as a query parameter? I would not like an option to be only accessible from the cmd line.

If it is could you did not add it to the query parameters section of the readme?
Also is there any automated test that one might think of for this? E.g. here to test the url parsing and here to verify that the custom title is correctly passed through to the generated report?

If you add these I would gladly accept the PR.