[PATCH] feat(rpc): return "providers" packages when querying by `name` or `name-desc`

[morganamilo]

> I think it would be like:
> HTTP GET /rpc/?v=5&type=provides&arg[]=java-environment&arg[]=libgala.so
> {"version":5,"type":"provides","resultcount":2,"results":
>   "java-environment": [] // might be list of package names or list of "info"
>   "libgala.so": []
> }
Pacman can "-S" and "-Ss" by provides so I would prefer to have the 
option to search by provides in type=info and type=search rather than a 
new type=provides. Also I would like each option to be indivudually 
settable, so "provides", "name" and "desc" can be set indipendantly.