remove "container" from container.py method names

Container-related methods recently moved to container.py no longer
need to have 'container' in their name as they are within the
container scope already.

Additonally it made it awkward to call from another module:

    from .. import container
    container.get_container_runtime()

dangerzone/cli.py

@@ -92,7 +92,7 @@ def cli_main(
             exit(1)
 
     # Ensure container is installed
-    container.install_container()
+    container.install()
 
     # Convert the document
     print_header("Converting document to safe PDF")

dangerzone/container.py

@@ -28,10 +28,11 @@ container_name = "dangerzone.rocks/dangerzone"
 
 
 class NoContainerTechException(Exception):
-    pass
+    def __init__(self, container_tech: str) -> None:
+        super().__init__(f"{container_tech} is not installed")
 
 
-def get_container_tech() -> str:
+def get_runtime_name() -> str:
     if platform.system() == "Linux":
         runtime_name = "podman"
     else:
@@ -40,14 +41,15 @@ def get_container_tech() -> str:
     return runtime_name
 
 
-def get_container_runtime() -> str:
-    runtime = shutil.which(get_container_tech())
+def get_runtime() -> str:
+    container_tech = get_runtime_name()
+    runtime = shutil.which(container_tech)
     if runtime is None:
-        raise NoContainerTechException(f"{runtime_name} is not installed")
+        raise NoContainerTechException(container_tech)
     return runtime
 
 
-def install_container() -> Optional[bool]:
+def install() -> Optional[bool]:
     """
     Make sure the podman container is installed. Linux only.
     """
@@ -58,7 +60,7 @@ def install_container() -> Optional[bool]:
     log.info("Installing Dangerzone container image...")
 
     p = subprocess.Popen(
-        [get_container_runtime(), "load"],
+        [get_runtime(), "load"],
         stdin=subprocess.PIPE,
         startupinfo=get_subprocess_startupinfo(),
     )
@@ -95,7 +97,7 @@ def is_container_installed() -> bool:
     installed = False
     found_image_id = subprocess.check_output(
         [
-            get_container_runtime(),
+            get_runtime(),
             "image",
             "list",
             "--format",
@@ -116,7 +118,7 @@ def is_container_installed() -> bool:
 
         try:
             subprocess.check_output(
-                [get_container_runtime(), "rmi", "--force", found_image_id],
+                [get_runtime(), "rmi", "--force", found_image_id],
                 startupinfo=get_subprocess_startupinfo(),
             )
         except:
@@ -151,9 +153,9 @@ def exec_container(
     extra_args: List[str] = [],
     stdout_callback: Callable[[str], None] = None,
 ) -> int:
-    container_runtime = container.get_container_runtime()
+    container_runtime = get_runtime()
 
-    if get_container_tech() == "podman":
+    if get_runtime_name() == "podman":
         platform_args = []
         security_args = ["--security-opt", "no-new-privileges"]
         security_args += ["--userns", "keep-id"]

dangerzone/gui/main_window.py

@@ -104,7 +104,7 @@ class InstallContainerThread(QtCore.QThread):
         self.global_common = global_common
 
     def run(self) -> None:
-        container.install_container()
+        container.install()
         self.finished.emit()
 
 
@@ -157,7 +157,7 @@ class WaitingWidget(QtWidgets.QWidget):
         state: Optional[str] = None
 
         try:
-            container_runtime = container.get_container_runtime()
+            container_runtime = container.get_runtime()
         except container.NoContainerTechException:
             log.error("Docker is not installed")
             state = "not_installed"