feat: add linux install script for manual installation support

scripts/install_linux.sh

@@ -0,0 +1,57 @@
+#!/bin/bash
+
+set -e
+
+observeagent_install_dir="/etc/observe-agent"
+tmp_dir="/tmp/observe-agent"
+
+if [ -z "$ZIP_DIR" ]; then
+    # Download the file from the latest release when there is no zip provided
+    echo "Downloading latest release from GitHub"
+    curl -L -o /tmp/observe-agent.tar.gz https://github.com/observeinc/observe-agent/releases/latest/download/observe-agent_Linux_$(arch).tar.gz
+    ZIP_DIR="/tmp/observe-agent.tar.gz"
+else
+    echo "Installing from provided zip file: $ZIP_DIR"
+fi
+
+# Set up the temp dir and extract files.
+rm -rf $tmp_dir
+mkdir -p $tmp_dir
+tar -xzf $ZIP_DIR -C $tmp_dir
+
+# If the observe-agent.yaml file already exists, leave it alone.
+# Otherwise we need to know what the collection endpoint and token are.
+if [ ! -f "$observeagent_install_dir/observe-agent.yaml" ]; then
+    if [ -z "$OBSERVE_URL" ]; then
+        echo "OBSERVE_URL env var is not set"
+        exit 1
+    fi
+
+    if [ -z "$TOKEN" ]; then
+        echo "TOKEN env var is not set"
+        exit 1
+    fi
+fi
+
+# Create the needed directories
+echo "Creating system install folders. This may ask for your password..."
+sudo mkdir -p $observeagent_install_dir /var/lib/observe-agent/filestorage
+sudo chmod +rw /var/lib/observe-agent/filestorage
+
+# Copy all files to the install dir.
+sudo cp -f $tmp_dir/observe-agent /usr/bin/observe-agent
+sudo cp -f $tmp_dir/otel-collector.yaml $observeagent_install_dir/otel-collector.yaml
+sudo rm -rf $observeagent_install_dir/connections
+sudo cp -fR $tmp_dir/connections $observeagent_install_dir/connections
+sudo chown -R root:root $observeagent_install_dir
+
+# Initialize the agent config file if it doesn't exist
+if [ -f "$observeagent_install_dir/observe-agent.yaml" ]; then
+    echo "Leaving existing observe-agent.yaml in place."
+else
+    echo "Initializing observe-agent.yaml"
+    sudo /usr/bin/observe-agent init-config --token $TOKEN --observe_url $OBSERVE_URL --config_path $observeagent_install_dir/observe-agent.yaml
+    sudo chown root:root $observeagent_install_dir/observe-agent.yaml
+fi
+
+echo "Observe agent successfully installed to $observeagent_install_dir"