Improve and document search utils

[edgarcosta]

These past days we have been tricked a couple of times by the count and search function giving different results.

We assumed that there was a bug in the count function, but what ended up happening is that some filterings were being applied to one and not the other.

We also messed up "cleaning" the database due to do this.

We need to add an option, to avoid any filtering, and we need to go through the work and make clear what are the arguments and keywords expected. Having functions with, "(*args, **kwds)" allows a lot of flexibility, but makes the usage quite opaque, especially, when we are under pressure to fix bugs affecting the live website.