feat: Add automated link checker to 'make verify'

[ajaysundark]

Our documentation contains many links to internal pages and external websites. To ensure a good user experience, we need to regularly check that these links are not broken.

This task is to create a script (hack/verify-links.sh) that automatically checks for broken links in all Markdown (.md) files and integrate it into our existing verification pipeline. The main verification script (hack/verify-all.sh) could then be updated to execute hack/verify-links.sh. Running make verify should successfully run the link checker over all .md files in the repository.

We can use docs/book/install-and-build-mdbook.sh as a reference for how to download a tool based on OS and architecture. The lychee tool is a good option for this purpose.

example, ref: containerd project has this workflow

[farazmd]

@ajaysundark - I would like to work on this

[ajaysundark]

Sure, thanks!

/assign @farazmd

[farazmd]

@ajaysundark - I've created a PR for this. The script uses CLI options to configure lychee, but we can also make use of a config file if needed. Let me know if you'd want me to switch to the config file instead