Add a script for running through some basic repository setup

Add a repository_setup.sh script that automates a couple of setup steps
for setup of new rust-vmm repositories. It also supports updating the
configuration of already created repositories by comparing the
repository's configuration to the defaults in rust-vmm-ci and giving the
option to update.

Currently, the script supports dependabot setup and .platform file
generation. It does not deal with the coverage files, since I am still
hoping to switch us over to codecov.io in the future, at which point
that will all changes completely anyway.

Signed-off-by: Patrick Roy <roypat@amazon.co.uk>

setup_repository.sh

@@ -0,0 +1,101 @@
+#!/bin/bash
+
+set -euo pipefail
+
+cat <<EOF
+Welcome to the rust-vmm interactive repository setup!
+
+This script will guide you through initializing basic components of a fresh
+rust-vmm repository, or alternatively lets you update the configuration of an
+existing repository (for example, if since the first setup of a repository,
+rust-vmm-ci has added new features that you would like to use).
+
+EOF
+
+RUST_VMM_CI=$(dirname ${BASH_SOURCE[0]})
+
+SUPPORTED_PLATFORMS=("x86_64" "aarch64" "riscv64")
+PLATFORMS_FILE=".platform"
+
+DEPENDABOT_SCHEDULES=("weekly" "monthly")
+DEPENDABOT_FILE=".github/dependabot.yml"
+
+confirm() {
+	read -p "$1 [Y/n] " -n 1 -r
+
+	if [ ! -z $REPLY ]; then
+		echo # move to new line unless user confirmed with just 'enter'
+	else
+		return 0
+	fi
+	[[ $REPLY =~ ^[Yy]$ ]]
+}
+
+setup_platforms_file() {
+	touch $PLATFORMS_FILE
+	echo "Please select the hardware plaforms for which you would like to enable CI support:"
+	for platform in "${SUPPORTED_PLATFORMS[@]}"; do
+		question="Enable support for $platform?"
+		if confirm "$question"; then 
+		       	echo $platform >> $PLATFORMS_FILE
+		fi
+	done
+}
+
+setup_dependabot_config() {
+	mkdir -p $(dirname $DEPENDABOT_FILE)
+	
+	cat <<EOF
+Dependabot allow you to automatically receive PRs for bumping your cargo
+dependencies, as well as for updating the rust-vmm-ci submodule. You can choose
+to run dependabot on different schedules: ${DEPENDABOT_SCHEDULES[@]}.
+
+Which schedule would you like to enable? (say 'n' to disable dependabot)
+EOF
+
+	select opt in "${DEPENDABOT_SCHEDULES[@]}"
+	do
+		selected_config=$RUST_VMM_CI/dependabot-$opt.yml
+
+		if [ -f $selected_config ]; then
+			cp $selected_config $DEPENDABOT_FILE
+			echo "Configured for $opt schedule"
+		else
+			echo "Not setting up dependabot"
+		fi
+		break
+	done
+}
+
+if [ -f $PLATFORMS_FILE ]; then
+	current_platforms=$(tr '\n' ' ' < $PLATFORMS_FILE)
+	question="This repository already has a $PLATFORMS_FILE file setup. Do you want to regenerate it? Current supported platforms are: $current_platforms"
+
+	if confirm "$question"; then
+		rm $PLATFORMS_FILE
+		setup_platforms_file
+	fi
+else
+	setup_platforms_file
+fi
+
+echo
+
+if [ -f "$DEPENDABOT_FILE" ]; then
+	well_defined=0
+	for schedule in "${DEPENDABOT_SCHEDULES[@]}"; do
+		if cmp --silent $RUST_VMM_CI/dependabot-$schedule.yml $DEPENDABOT_FILE; then
+			echo -n "Dependabot is already setup for the $schedule schedule. "
+			well_defined=1
+		fi
+	done
+	if [ $well_defined -eq 0 ]; then
+		echo -n "Dependabot is already configured, although configuration does not match any rust-vmm-ci provided ones. "
+	fi
+	if confirm "Would you like to reconfigure dependabot?"; then
+		rm $DEPENDABOT_FILE
+		setup_dependabot_config
+	fi
+else
+	setup_dependabot_config
+fi