[OpenSER-Docs] Add examples in module documentation

Hi, for now they are just a few modules that include real examples in their doc. Usually, a module doc just shows examples of how to set each parameter or use each function, but there is not a "global" example. I don't know if would be good to include a section "Examples" in the module doc template (it could saturate the info), or maybe a section "Examples" containing links to the wiki or external references. What do you think about it? -- Iñaki Baz Castillo ibc(a)in.ilimit.es