Add Java Encoder and Java HTML Sanitizer projects

[jgadsden]

Describe what content should be added :

It would be good if these libraries had their own ~~pages~~ page :

OWASP Java Encoder project OWASP Java HTML Sanitizer project

Context :

Section: 05-implementation/03-secure-libraries

Declaration:

Please make sure you have:

• [x] read the contribution guide and agree to the Code of Conduct
• [x] not used agentic or generative AI in creating this issue

Context: