TMT: Install bats from source on RHEL

bats isn't shipped on ELN, RHEL and CentOS Stream. Enabling EPEL is also
problematic on internal testing farm environments.

This commit fetches and installs bats from source on RHEL and CentOS
Stream so we don't have to worry about EPEL enablement anymore.

We also aren't doing any ELN testing on TMT currently, so we don't need
any additional configuration for it and the current config should work
across the board.

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>

plans/main.fmf

@@ -6,8 +6,14 @@ prepare:
     - when: distro == centos-stream or distro == rhel
       how: shell
       script: |
-        dnf -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-$(rpm --eval '%{?rhel}').noarch.rpm
-        dnf -y config-manager --set-enabled epel
+        # Install bats
+        # https://bats-core.readthedocs.io/en/stable/installation.html
+        BATS_VERSION=1.12.0
+        curl -L https://github.com/bats-core/bats-core/archive/refs/tags/v"$BATS_VERSION".tar.gz | tar -xz
+        pushd bats-core-"$BATS_VERSION"
+        ./install.sh /usr
+        popd
+        rm -rf bats-core-"$BATS_VERSION"
       order: 10
     - when: initiator == packit
       how: shell

systemtest/tmt/main.fmf

@@ -1,5 +1,4 @@
 require:
-    - bats
     - skopeo-tests
 
 environment: