Add vim-extra package

[nathanweeks]

The vim-extra package adds various features that allow vim to be used more productively, such as plugins and syntax files. For comparison, the GCP, IBM, Oracle, and AWS Cloud Shells all have an equivalent package preinstalled.

Fixes #245

Has an install size of ~35M:

root [ / ]# yum info --installed vim-extra                              
Loaded plugin: tdnfrepogpgcheck                                         
Name          : vim-extra                                               
Arch          : x86_64                                                  
Epoch         : 0                                                       
Version       : 9.0.2121                                                
Release       : 2.cm2                                                   
Install Size  :  35.34M (37056166)                                      
Repo          : @System                                                 
Summary       : Extra files for Vim text editor                         
URL           : https://www.vim.org                                     
License       : Vim                                                     
Description   : The vim extra package contains a extra files for powerful text editor.                                                          
                                                                        
                                                                        
Total Size:  35.34M (37056166)