Document that map projection is read from project

Author: manisandro

src/configuration/ThemesConfiguration.md

@@ -14,6 +14,7 @@ The first step is to prepare a QGIS project for publishing. Besides the common t
 
 | What                 | Where                                     | Description                                      |
 |----------------------|-------------------------------------------|--------------------------------------------------|
+| Map projection       | Project Properties → CRS             | Map projection used in QWC.                      |
 | Service Metadata     | Project Properties → QGIS Server → Service capabilities | Shown in the theme info dialog, invokable from the Layer Tree panel titlebar. |
 | Title, keywords      | Project Properties → QGIS Server → Service capabilities | Theme title, displayed in the Theme Switcher, and keywords, useful for filtering. |
 | Map extent           | Project Properties → QGIS Server → WMS → Advertised extent | The extent used as initial map extent when loading the theme, unless overridden in `themesConfig.json`. |
@@ -59,7 +60,7 @@ The next step is to configure the theme for QWC. There are two approaches:
 
 ### Automatic theme configuration <a name="automatic-theme-configuration"></a>
 
-When using `qwc-docker`, save your QGIS projects below `qwc-docker/volumes/qgs-resources/scan`. Adjust the default settings (`defaultMapCrs`, `defaultBackgroundLayers`, etc.) as desired in `qwc-docker/volumes/config-in/<tentant>/themesConfig.json`. Then [generate the theme configuration](#generating-theme-configuration).
+When using `qwc-docker`, save your QGIS projects below `qwc-docker/volumes/qgs-resources/scan`. Adjust the default settings (`defaultBackgroundLayers`, `defaultSearchProviders`, etc.) as desired in `qwc-docker/volumes/config-in/<tentant>/themesConfig.json`. Then [generate the theme configuration](#generating-theme-configuration).
 
 You can configure an automatically configured theme as default theme by setting `defaultTheme` in `themesConfig.json` to the path to the QGIS project file below `qwc-docker/volumes/qgs-resources`, without the `.qgs` extension. For example to set `qwc-docker/volumes/qgs-resources/scan/project.qgs` as default theme, you'd write
 
@@ -112,7 +113,6 @@ The `themesConfig.json` file contains a list of themes, optionally organized in
       ...
     ],
   },
-  "defaultMapCrs": "<Default map crs, defaults to EPSG:3857>",
   "defaultBackgroundLayers": "<Default background layers, see theme definition below>",
   "defaultWMSVersion": "<Default WMS version, i.e. 1.3.0>",
   "defaultScales": [<Scale denominators, see theme definition below>],
@@ -134,7 +134,7 @@ The format of the theme definitions is as follows:
 |-------------------------------------------------|-----------------------------------------------------------------------------------|
 | `"id": "<id>",`                                 | Theme identificator. Autogenerated if not specified.                              |
 | `"url": "<WMS URL>",`                           | The address of desired WMS served by QGIS Server.                                 |
-| `"mapCrs": "<EPSG code>",`                      | Optional, map projection, defaults to `defaultMapCrs`.                            |
+| `"mapCrs": "<EPSG code>",`                      | Optional, map projection, defaults to project projection.                         |
 | `"wmsOnly": <true|false>`                       | Optional, whether the entry should only be configured as a WMS, and not as a theme. |
 | `"title": "<Custom title>",`                    | Optional, override WMS title.                                                     |
 | `"description": "<Description>",`               | Optional, an additional description to show below the theme title.                |