[CI] Script to help know if localized pages need updating

[chalin]

• Prep for [i18n] Propose way to associate translations to specific commit of default lang page #4582
• Adds a script to help us know if localized pages need updating
• See the script help for details
• Edit: I renamed the script from the K8s name of lsync.sh to scripts/i18n-check.sh.

For example, this is what it outputs for zh using verbose mode:

$ ./scripts/i18n-check.sh -v content/zh          
1       1       content/en/docs/demo/_index.md
File is in sync content/zh/docs/what-is-opentelemetry.md
30      30      content/en/docs/concepts/components.md
File is in sync content/zh/docs/concepts/semantic-conventions.md
File is in sync content/zh/docs/concepts/_index.md
1       1       content/en/docs/kubernetes/_index.md
File is in sync content/zh/docs/_index.md
13      1       content/en/_index.md

Use -d to see the detailed page diff, for example:

$ ./scripts/i18n-check.sh -d content/zh/docs/kubernetes

Will output:

diff --git a/content/en/docs/kubernetes/_index.md b/content/en/docs/kubernetes/_index.md
index 3592df5d..c7980653 100644
--- a/content/en/docs/kubernetes/_index.md
+++ b/content/en/docs/kubernetes/_index.md
@@ -1,7 +1,7 @@
 ---
 title: OpenTelemetry with Kubernetes
 linkTitle: Kubernetes
-weight: 11
+weight: 350
 description: Using OpenTelemetry with Kubernetes
 ---

/cc @open-telemetry/docs-zh-approvers @ymotongpoo