Describe features covered by the minimal package (#3472)

* Describe features covered by the minimal package

Let's be a bit more specific about the features which are covered
by the minimal ``tmt`` package.

* Update the `minimal` install description, mention in the guide

* Mention that `ansible` is a weak dependency

docs/guide.rst

@@ -19,7 +19,8 @@ The First Steps
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Installing the main package with the core functionality is quite
-straightforward. No worry, there are just a few dependencies:
+straightforward. No worry, the :ref:`/stories/install/minimal`
+package has just a few dependencies:
 
 .. code-block:: shell
 
@@ -85,8 +86,8 @@ dependencies here:
     tmt run -a provision -h virtual
 
 Don't care about the disk space? Simply install ``tmt+all`` and
-you'll get all available functionality at hand. Check the help to
-list all supported provision methods:
+you'll get :ref:`/stories/install/all` available functionality at
+hand. Check the help to list all supported provision methods:
 
 .. code-block:: shell
 

stories/install.fmf

@@ -6,6 +6,29 @@ link:
 
 /minimal:
     summary: Minimal tmt installation with core features only
+    description: |
+        The minimal package provides basic functionality which
+        covers mainly these areas:
+
+        * explore and lint existing tests, plans and stories
+        * create new tests, plans and stories from templates
+        * execute tests on the :ref:`/plugins/provision/local`
+          host or :ref:`/plugins/provision/connect` to a remote
+          guest using ssh
+        * prepare guest using the
+          :ref:`/plugins/prepare/ansible`,
+          :ref:`/plugins/prepare/feature`,
+          :ref:`/plugins/prepare/install` and
+          :ref:`/plugins/prepare/shell` plugins
+        * report test results to :ref:`/plugins/report/display`
+          or into an :ref:`/plugins/report/html` page
+
+        .. note::
+
+            If you are used to install packages without optional
+            dependencies, ansible features might not be working as
+            they are a weak dependency of the minimal package.
+
     example: dnf install tmt
     link+:
       - verified-by: /plans/install/minimal