Add an API log

Add an API log

During incident response, it was not possible to tell what API modules
were being requested and by whom, since the action parameter is often
posted. This change logs the API parameters whether they are posted or
sent in the query string.

I did try to get the API parameters from the module, but that turns out
to be difficult. Modules create submodules (generators, page sets) as
local variables, which are created in a procedural style and destroyed
before logging is done, so there is no easy way to query them for
parameter lists after execution completes.

In ApiOptionsTest, use a real ApiMain object like all the other API test
cases, rather than a mock object. Otherwise the test fails.

Change-Id: Idc786007fe61811d1874f29b5ce4762dd97b1847