support for pelias api

Pelias is opensource geocoder software available at https://www.pelias.io
This feature adds support for pelias as alternative to geonames
Feature will add a extra setting to select the type of geocoder api (geonames or pelias)

An example of pelias api implementation is https://eines.icgc.cat/geocodificador/autocompletar?text=girona&layers=mun

Work is contributed by ICGC.cat

Start by locating the existing GeoNames geocoder integration and the setting that selects geocoder behavior. Use the Pelias API example at https://eines.icgc.cat/geocodificador/autocompletar?text=girona&layers=mun to understand the alternative request, and consider the feature complete when users can select Pelias or GeoNames and geocoding works through the selected API.

Written by the indexing model from the issue text.