Token filters - stemmer [DOC]

[AntonEliatra]

What do you want to do?

• [ ] Request a change to existing documentation
• [x] Add new documentation
• [ ] Report a technical problem with the documentation
• [ ] Other

Create a separate page for Token filter: stemmer

Part of META issue: https://github.com/opensearch-project/documentation-website/issues/1483

*Version: all

[AntonEliatra]

@vagimeli I can take this one