feat: add init.sh post-initialization script (#88)

Add a post-initialization script that replaces all instances of
function-template-python with the user's function name in:
- package/crossplane.yaml (the Function resource name)
- example/*.yaml (example function references)

This enables the Crossplane CLI's xpkg init command to properly
initialize the template by running the init.sh hook automatically.

Fixes #88

Signed-off-by: Moritz Schmitz von Hülst <moritz@schmitzvonhuelst.de>

Author: boxcee

init.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+# This script helps initialize a new function project by
+# replacing all instances of function-template-python with the
+# name of your function. The script accepts two arguments:
+# 1. The name of your function
+# 2. The path to your function directory
+
+set -e
+
+cd "$2" || return
+
+# Replace function-template-python with the name of your function
+# in package/crossplane.yaml
+perl -pi -e s,function-template-python,"$1",g package/crossplane.yaml
+# in example YAML files
+find example -type f -print0 | xargs -0 -I {} perl -pi -e s,function-template-python,"$1",g {}
+
+echo "Function $1 has been initialized successfully"