Add Java Runner support

[piraz]

Create a runner feature to execute Java code in chase.nvim.

What it should do

• Allow running .java files directly from chase.nvim
• Configure the command to compile and run Java according to the operating system
• Display process output in the terminal buffer
• Allow customization of environment variables and JVM arguments
• Document usage in the README

Benefits

• Makes Java development easier for Neovim users
• Integrates with existing commands for other languages

Acceptance criteria

• It is possible to run any .java file in a straightforward way
• Option to customize commands/arguments
• Clear documentation and usage examples