CMake: tidy up automatic linking of Calamares libraries

- Modules and plugins don't need to mention libcalamares themselves
  for linking -- we can do that automatically. Use the IMPORTED names
  so that it works in Calamares main repo and external repositories.
- Complain about unknown module types.

CMakeModules/CalamaresAddPlugin.cmake

@@ -126,6 +126,15 @@ function( calamares_add_plugin )
     # create target name once for convenience
     set( target "calamares_${PLUGIN_TYPE}_${PLUGIN_NAME}" )
 
+    # automatic library linkage
+    if(PLUGIN_TYPE STREQUAL "view" OR PLUGIN_TYPE STREQUAL "viewmodule")
+        list(APPEND PLUGIN_LINK_PRIVATE_LIBRARIES Calamares::calamaresui)
+    elseif(PLUGIN_TYPE STREQUAL "job")
+        list(APPEND PLUGIN_LINK_PRIVATE_LIBRARIES Calamares::calamares)
+    else()
+        message(FATAL_ERROR "Unknown plugin type ${PLUGIN_TYPE}")
+    endif()
+
     # determine target type
     if( NOT ${PLUGIN_SHARED_LIB} )
         set( target_type "MODULE" )

CMakeModules/CalamaresAddTest.cmake

@@ -36,7 +36,7 @@ function( calamares_add_test )
             TEST_NAME
                 ${TEST_NAME}
             LINK_LIBRARIES
-                calamares
+                Calamares::calamares
                 ${TEST_LIBRARIES}
                 Qt5::Core
                 Qt5::Test
@@ -46,7 +46,7 @@ function( calamares_add_test )
         # compiled, so that it can find test-files in that source dir.
         target_compile_definitions( ${TEST_NAME} PRIVATE -DBUILD_AS_TEST="${CMAKE_CURRENT_SOURCE_DIR}"  ${TEST_DEFINITIONS} )
         if( TEST_GUI )
-            target_link_libraries( ${TEST_NAME} calamaresui Qt5::Gui )
+            target_link_libraries( ${TEST_NAME} Calamares::calamaresui Qt5::Gui )
         endif()
         if( TEST_RESOURCES )
             calamares_autorcc( ${TEST_NAME} ${TEST_RESOURCES} )