fix: move gitbrowse utils to utils folder

[schlerp]

This pull request updates the naming of a utility function and its usage in the Neovim configuration for git browsing actions. The changes are focused on improving code clarity and consistency by renaming both the function and its references.

Function and usage renaming for clarity:

• Renamed the function build_gitbrows_config to build_gitbrowse_options in nvim/lua/core/utils/gitbrowse.lua (previously gitbrowse_utils.lua) to better reflect its purpose and improve code readability.
• Updated all references to build_gitbrows_config to use the new name build_gitbrowse_options in the git browse key mappings in nvim/lua/config/keys.lua. [1] [2] [3] [4]