Add ability for plugins to specify logToBuffer and keepOpen without CLI options

[austinmatherne-wk]

What should we change and why?

As mentioned in Arelle/ixbrl-viewer#568 (comment), the way Arelle handles logToBuffer and keepOpen is awkward. Arelle doesn't define a command line option for logToBuffer, but does check if a plugin has.

A related issue, Arelle specifies a keepOpen argument, but this also seems to be a setting that should be controlled by plugins and not the user at the command line.

Both of these could be solved by introducing a mechanism (plugin hook?) for plugins to directly define options on the controller without going through the command line options.