Closes #10696: Break out instructions for installing & removing plugins (#15757)

* Closes #10696: Break out instructions for installing & rmeoving plugins

* Misc cleanup

docs/plugins/installation.md

@@ -0,0 +1,68 @@
+# Installing a Plugin
+
+!!! warning
+    The instructions below detail the general process for installing and configuring a NetBox plugin. However, each plugin is different and may require additional tasks or modifications to the steps below. Always consult the documentation for a specific plugin **before** attempting to install it.
+
+## Install the Python Package
+
+Download and install the plugin's Python package per its installation instructions. Plugins published via PyPI are typically installed using the [`pip`](https://packaging.python.org/en/latest/tutorials/installing-packages/) command line utility. Be sure to install the plugin within NetBox's virtual environment.
+
+```no-highlight
+$ source /opt/netbox/venv/bin/activate
+(venv) $ pip install <package>
+```
+
+Alternatively, you may wish to install the plugin manually by running `python setup.py install`. If you are developing a plugin and want to install it only temporarily, run `python setup.py develop` instead.
+
+## Enable the Plugin
+
+In `configuration.py`, add the plugin's name to the `PLUGINS` list:
+
+```python
+PLUGINS = [
+    # ...
+    'plugin_name',
+]
+```
+
+## Configure the Plugin
+
+If the plugin requires any configuration, define it in `configuration.py` under the `PLUGINS_CONFIG` parameter. The available configuration parameters should be detailed in the plugin's `README` file or other documentation.
+
+```no-highlight
+PLUGINS_CONFIG = {
+    'plugin_name': {
+        'foo': 'bar',
+        'buzz': 'bazz'
+    }
+}
+```
+
+## Run Database Migrations
+
+If the plugin introduces new database models, run the provided schema migrations:
+
+```no-highlight
+(venv) $ cd /opt/netbox/netbox/
+(venv) $ python3 manage.py migrate
+```
+
+!!! tip
+    It's okay to run the `migrate` management command even if the plugin does not include any migration files.
+
+## Collect Static Files
+
+Plugins may package static resources like images or scripts to be served directly by the HTTP front end. Ensure that these are copied to the static root directory with the `collectstatic` management command:
+
+```no-highlight
+(venv) $ cd /opt/netbox/netbox/
+(venv) $ python3 manage.py collectstatic
+```
+
+### Restart WSGI Service
+
+Finally, restart the WSGI service and RQ workers to load the new plugin:
+
+```no-highlight
+# sudo systemctl restart netbox netbox-rq
+```