Emacs:git: configure fci-rule-column to 72

- Configure fci-rule-column to 72 when git-commit-mode is enabled.
- Set fci-rule-column to 80 when git-commit is done

Tested-by: Ratheesh S <ratheeshreddy@gmail.com>
Signed-off-by: Ratheesh S <ratheeshreddy@gmail.com>
Emacs:git: configure gitconfig and gitignore mode

Configure gitconfig-mode and gitignore-mode and add them to default
package list.

Tested-by: Ratheesh S <ratheeshreddy@gmail.com>
Signed-off-by: Ratheesh S <ratheeshreddy@gmail.com>