Instructions for building the tutorial single-node image are not up to date

[vkarak]

After the change in the installation method and the removal of the ./bootstrap.sh scripts, the instruction to build the tutorial container is not working:

» podman build -t reframe-tut-singlenode:latest -f examples/tutorial/dockerfiles/singlenode.Dockerfile .
STEP 1/13: FROM ubuntu:22.04
STEP 2/13: RUN apt-get -y update &&     apt-get -y install curl &&     apt-get -y install sudo &&     apt-get -y install python3-pip &&     apt-get -y install clang gcc git jq libomp-dev tree vim
--> Using cache cdb7bfdf31cd41db7af5c4f46b2b9c2de2c8bdda6b3f389d1a82646a991d1711
--> cdb7bfdf31cd
STEP 3/13: ARG REFRAME_TAG=develop
--> Using cache 8e279464ae8dee87d9929393715497fea3413e06bd482d197dcba1acf4a22c3d
--> 8e279464ae8d
STEP 4/13: ARG REFRAME_REPO=reframe-hpc
--> Using cache 2adfb4d5b8921c8ea3c09adbe496f89fd53fe8f1fc9686ee03ea75222656e8a7
--> 2adfb4d5b892
STEP 5/13: WORKDIR /usr/local/share
--> Using cache d6eed2a9b94358ec75de266e542afcd1edbc9bf26d2b28320d9ca99c075b9a89
--> d6eed2a9b943
STEP 6/13: COPY . /usr/local/share/reframe
--> d5b95a6aec7a
STEP 7/13: RUN cd reframe && ./bootstrap.sh
/bin/sh: 1: ./bootstrap.sh: not found
Error: building at STEP "RUN cd reframe && ./bootstrap.sh": while running runtime: exit status 127