leaflet 10.0.0

10.0.0 release implemented functionalities:
- full support for Drupal 10;
- backward compatibility for Leaflet module 2.2.x
- implementation of Leaflet Views Grouping, reflecting into Leaflet Control Overlays, with:
- options to initially disable specific Groups and/or not include them in the Leaflet Overlays Control;
- Markerclustering support;
- specific/additional hook_leaflet_views_features_group_alter to alter Leaflet View Group definitions;
- featured implementation to dynamically exclude specific Leaflet Features from being Markercluster-ed (“Markercluster excluded” element/flag);
- full Implementation / support of Leaflet Tooltips (https://leafletjs.com/reference.html#tooltip), with custom Json options, tokens & replacements patterns;
- extended support for Leaflet Popups (https://leafletjs.com/reference.html#popup), with custom Json options, tokens & replacements patterns;
- full Implementation / support of User Location Control via Leaflet.Locate plugin (https://github.com/domoritz/leaflet-locatecontrol), with custom Json options, tokens & replacements patterns;
- full implementation / support for Reset Map View Control via Leaflet.ResetView plugin (https://github.com/drustack/Leaflet.ResetView), with custom Json options, tokens & replacements patterns;
- implementation of Leaflet Feature Additional Properties (with custom Json options, tokens & replacements patterns) for advanced and dynamic customisation of Leaflet Map and Features rendering logics;

Code Refactoring & clean up:
- cleanup / removal of deprecated and un-usable Leaflet Views plugins.
- extended refactoring of Leaflet module js code, to allow easier extension/customisation of Drupal.leaflet.prototype and Drupal.leaflet_widget.prototype methods, with extended objects, functions and methods documentation;
- embedding all Leaflet Js libraries dependencies into the the module, for better Ajax and advanced Fields Widgets compatibilities (Inline Entity Form, Paragraphs Widgets supports, etc.)
- general Drupal/PHP & JS better refactoring, complying with correct Coding Standards;

Readme.md file updated to include new 10.0.0 release istructions.