Add section "GUI"

Section provides a brief overview of the web interface

Signed-off-by: Dylan Whyte <d.whyte@proxmox.com>

docs/gui.rst

@@ -0,0 +1,135 @@
+Graphical User Interface
+========================
+
+Proxmox Backup Server offers an integrated, web-based interface to manage the
+server. This means that you can carry out all administration tasks through your
+web browser, and that you don't have to worry about installing extra management
+tools. The web interface also provides a built in console, so if you prefer the
+command line or need some extra control, you have this option.
+
+The web interface can be accessed via https://youripaddress:8007. The default
+login is `root`, and the password is the one specified during the installation
+process.
+
+
+Features
+--------
+
+* Simple management interface for Proxmox Backup Server
+* Monitoring of tasks, logs and resource usage
+* Management of users, permissions, datastores, etc.
+* Secure HTML5 console
+* Support for multiple authentication sources
+* Support for multiple languages
+* Based on ExtJS 6.x JavaScript framework
+
+
+Login
+-----
+
+.. image:: images/screenshots/pbs-gui-login-window.png
+  :width: 250
+  :align: right
+  :alt: PBS login window
+
+When you connect to the web interface, you will first see the login window.
+Proxmox Backup Server supports various languages and authentication backends
+(*Realms*), both of which can be selected here.
+
+.. note:: For convenience, you can save the username on the client side, by
+  selecting the "Save User name" checkbox at the bottom of the window.
+
+
+GUI Overview
+------------
+
+.. image:: images/screenshots/pbs-gui-dashboard.png
+  :width: 250
+  :align: right
+  :alt: PBS GUI Dashboard
+
+The Proxmox Backup Server web interface consists of 3 main sections:
+
+* **Header**: At the top. This shows version information, and contains buttons to view
+  documentation, monitor running tasks, and logout.
+* **Sidebar**: On the left. This contains the configuration options for
+  the server.
+* **Configuration Panel**: In the center. This contains the control interface for the
+  configuration options in the *Sidebar*.
+
+
+Sidebar
+-------
+
+In the sidebar, on the left side of the page, you can see various items relating
+to specific management activities.
+
+
+Dashboard
+^^^^^^^^^
+
+The Dashboard shows a summary of activity and resource usage on the server.
+Specifically, this displays hardware usage, a summary of
+previous and currently running tasks, and subscription information.
+
+
+Configuration
+^^^^^^^^^^^^^
+
+The Configuration section contains some system configuration options, such as
+time and network configuration. It also contains the following subsections:
+
+* **User Management**: Add users and manage accounts
+* **Permissions**: Manage permissions for various users
+* **Remotes**: Add, edit and remove remotes (see :term:`Remote`)
+* **Sync Jobs**: Manage and run sync jobs to remotes
+* **Subscription**: Upload a subscription key and view subscription status
+
+
+Administration
+^^^^^^^^^^^^^^
+
+.. image:: images/screenshots/pbs-gui-administration-serverstatus.png
+  :width: 250
+  :align: right
+  :alt: Administration: Server Status overview
+
+The Administration section contains a top panel, with further administration
+tasks and information. These are:
+
+* **ServerStatus**: Provides access to the console, power options, and various
+  resource usage statistics
+* **Services**: Manage and monitor system services
+* **Updates**: An interface for upgrading packages
+* **Syslog**: View log messages from the server
+* **Tasks**: Task history with multiple filter options
+
+.. image:: images/screenshots/pbs-gui-disks.png
+  :width: 250
+  :align: right
+  :alt: Administration: Disks
+
+The administration menu item also contains a disk management subsection:
+
+* **Disks**: View information on available disks
+
+  * **Directory**: Create and view information on *ext4* and *xfs* disks
+  * **ZFS**: Create and view information on *ZFS* disks 
+
+
+Datastore
+^^^^^^^^^
+
+.. image:: images/screenshots/pbs-gui-datastore.png
+  :width: 250
+  :align: right
+  :alt: Datastore Configuration
+
+The Datastore section provides an interface for creating and managing
+datastores. It contains a subsection for each datastore on the system, in
+which you can use the top panel to view:
+
+* **Content**: Information on the datastore's backup groups and their respective
+  contents
+* **Statistics**: Usage statistics for the datastore
+* **Permissions**: View and manage permissions for the datastore