[DOC] Review and complete the Runtimes section

[d4rkstar]

Why you need it?

The Runtimes section should contains relevant information about OpenServerless supported runtimes

How it could be?

We should probably:

• Start to document better the far most used runtimes like Nodejs, Python and Php, removing the other runtimes (like Go and Java)
• In a second step, we should review Go and Java and re-add them back to the documentation.
• For each runtime, we should indicate versions supported and runtime libraries available by default

Other related information

Probably we can reuse some documentation from here:

• https://nuvolaris.github.io/nuvolaris/3.1.0/development/actions-nodejs.html
• https://nuvolaris.github.io/nuvolaris/3.1.0/development/actions-python.html
• https://nuvolaris.github.io/nuvolaris/3.1.0/development/actions-php.html

Supported runtimes are here:

• https://github.com/apache/openserverless-runtimes/tree/main/runtime