[Lizmap] Lizmap Web Client and QGIS 3 : finally compatible

[René-Luc Dhont]

We are pleased to announce the release of lizmap web client 3.3 - [1] - 
and lizmap plugin 3.1 - [2] - [3]

These versions propose new features:

* Add French Address database BAN search
* Create HTML tooltip from QGIS drag&drop form
* Improve the HTML tooltip form: get the represented value
* Add filter form capabilities for PostgreSQL/PostGIS layers

But the main feature is QGIS Server 3 support [4].

For that we needed to adapt lizmap web client to QGIS Server changes and 
fix QGIS Server 3.4 in order to propose an identical user experience:

* Fix regression server print selection pdf
* JPEG output for WMS GetPrint request has gone
* In WMS GetFeatureInfo CRS param not mandatory when FILTER param
* Add unit test for WFS GetFeature with BBOX param without EPSG
* SLD : Support escapeChar attribute of PropertyIsLike
* Null field value in GML has to be empty string
* Use Project selection color in GetPrint
* Unit-test: To avoid regression in Server printing to PDF output format
* Keeps empty parts for not empty styles parameters

We also needed to update some useful QGIS Server plugins for Lizmap:

* Atlas print [5]
* WFS output Extension [6]

If you already use Lizmap Web Client, you can:

* update Lizmap Web Client to 3.3
* update QGIS Server to 3.4
* update the QGIS Server plugins you use
* go to the Lizmap Web client backoffice to update the QGIS Server 
version in configuration
* update your Lizmap Plugin to 3.1 in you QGIS 3.4 Desktop
* and update your QGIS projects.

If you want to test lizmap, install the lastest version with QGIS Server 
LTR.

1/ https://github.com/3liz/lizmap-web-client/releases/tag/3.3.0 
Lizmap-Web-Client - Release version 3.3.0
2/ http://plugins.qgis.org/plugins/lizmap/version/3.1.0/ Lizmap 3.1.0
3/ http://plugins.qgis.org/plugins/lizmap/version/3.1.1/ Lizmap 3.1.1
4/ https://github.com/3liz/lizmap-web-client/issues/1075 Compatibility 
with QGIS3
5/ https://github.com/3liz/qgis-atlasprint/releases/tag/v1.2.2 QGIS 
Server Atlas Print v1.2.2
6/ https://github.com/3liz/qgis-wfsOutputExtension/releases/tag/v1.2.2 
QGIS Server WFS Output Extension v1.2.2