Unsupported dynamic URLs in custom HTML pages about thunder

[RohanNagar]

Work is in progress on the url branch

[RohanNagar]

TODO still:

• Use UriInfo instead of configuration option
• Add optional customization option for replacement string (will probably tackle this in a new PR. For now, custom pages must use CODEGEN-URL)
• Add warning if String.contains("CODEGEN-URL") is false
• Use baseUriBuilder ? https://www.mail-archive.com/[email protected]/msg34526.html
• Tests
• Cleanup

[RohanNagar]

Instead of the baseUrl configuration option, we can do better by using @Context UriInfo uriInfo

https://stackoverflow.com/questions/7652321/getting-the-base-url-of-my-server-with-jax-rs

[RohanNagar]

Will open a new PR for customizing the replacement string.