Filtering module selection depending e.g. on indexing support

**Is your feature request related to a problem? Please describe.**

Some use cases require indexing, to be able to e.g. efficiently work on a document. They thus need a module that supports this.

Other use cases do not need it, and can be fine with using modules with higher rendering but no indexing support.

**Describe the solution you'd like**

Not sure exactly where this will fit. Of course it will be easy to make spd know which modules support what. The question is rather the interfacing with the user.

It would be easy to add filtering support for self-voicing application to decide which module to use depending on the availability of indexing.

The question is rather for the Orca case, possibly it'd have two selection boxes, to let the user choose which module is desired for the indexing case, and which is desired for the non-indexing case. It however needs to know when the user wants what, possibly through the command used to trigger some speech?