Enable relevant tests from the shared shell repo

This pull request enables tests in the Fedora CI using `tmt` which
also allows to easily execute and debug tests from your laptop:

Run tests directly on your localhost:

    sudo dnf install -y tmt
    tmt run --all provision --how local

Run tests in a virtual machine:

    sudo dnf install -y tmt-provision-virtual
    tmt run

Check the documentation to learn more about the tool:
https://docs.fedoraproject.org/en-US/ci/tmt/

.fmf/version

@@ -0,0 +1 @@
+1

plans/shell.fmf

@@ -0,0 +1,14 @@
+summary:
+    Run relevant tests from the shell tests repository
+discover:
+    how: fmf
+    url: https://src.fedoraproject.org/tests/shell
+    filter: component:ksh
+prepare:
+    how: install
+    package: ksh
+execute:
+    how: tmt
+environment:
+    PACKAGES: ksh
+    SH_BIN: ksh

tests/tests.yml

@@ -1,36 +0,0 @@
----
-
-# Tests that run in classic context
-- hosts: localhost
-  roles:
-  - role: standard-test-beakerlib
-    tags:
-    - classic
-    repositories:
-    - repo: "https://src.fedoraproject.org/tests/shell.git"
-      dest: "shell"
-      fmf_filter: "tier: 1, 2 & tags: classic"
-    environment:
-      PACKAGES: ksh
-      SH_BIN: ksh
-    required_packages:
-    - ksh
-    - expect            # login requires expect
-    - which             # smoke requires which
-
-# Tests that run in container
-- hosts: localhost
-  roles:
-  - role: standard-test-beakerlib
-    tags:
-    - container
-    repositories:
-    - repo: "https://src.fedoraproject.org/tests/shell.git"
-      dest: "shell"
-      fmf_filter: "tier: 1, 2 & tags: container, atomic"
-    environment:
-      PACKAGES: ksh
-      SH_BIN: ksh
-    required_packages:
-    - ksh
-    - which             # smoke requires which