Docker fix (#8835)

* Fix server command in Dockerfile

* Ensure invoke is installed into the venv

* Run extra check in docker build step

* Improve documentation

* Intercept ModuleNotFoundError

- Clear error message

* Docs updates

* Add extra check to dev docker build

* Cleanup tasks.py

* Prevent double activation of venv

* Change order of operations

---------

Co-authored-by: Matthias Mair <code@mjmair.com>

docs/docs/faq.md

@@ -26,7 +26,7 @@ Refer to the [invoke guide](./start/invoke.md#cant-find-any-collection-named-tas
 
 If the installed version of invoke is too old, users may see error messages during the installation procedure. Refer to the [invoke guide](./start/invoke.md#minimum-version) for more information.
 
-### No module named 'django'
+### No module named <xxx>
 
 During the install or update process, you may be presented with an error like:
 
@@ -34,9 +34,27 @@ During the install or update process, you may be presented with an error like:
 ModuleNotFoundError: No module named 'django'
 ```
 
-Most likely you are trying to run the InvenTree server from outside the context of the virtual environment where the required python libraries are installed.
+Either the named modules are not installed, or the virtual environment is not correctly activated.
 
-Always activate the virtual environment before running server commands!
+**Check Virtual Environment**
+
+Ensure that the virtual environment is correctly activated before running any InvenTree commands.
+
+**Check Invoke Tool**
+
+Ensure that the invoke tool is correctly installed inside the virtual environment, with:
+
+```bash
+pip install --upgrade --ignore-installed invoke
+```
+
+**Install Required Python Packages**
+
+Ensure that all required python packages are installed by running:
+
+```bash
+invoke install
+```
 
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