patch 8.2.3300: Lua: can only execute on Vim command at a time

patch 8.2.3300: Lua: can only execute on Vim command at a time

Problem:    Lua: can only execute on Vim command at a time.  Not easy to get
            the Vim version.
Solution:   Make vim.command() accept multiple lines.  Add vim.version().
            (Yegappan Lakshmanan, closes #8716)