Add SAML SP status to Feature Comparison docs (#20743)

Add SAML SP status to Feature Comparison docs (#20743)

* Add SAML SP integration

Add current SAML 2.0 Service Provider (SP) status. RhodeCode EE supports SAML, CE does not.

Included issue links for both Gitea and Gogs, as corporate users will likely be interested in the status of both.

* Add SAML SP status to comparison for other translations

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>