Upgrade instructions #186
Description
In
https://github.com/3liz/lizmap-web-client/blob/master/UPGRADE.md#replace-lizmap-files
it is suggested to replace lizmap files. IMHO it is better from all viewpoints to have a new install, and switch it after checking that it is working.
Moreover, upgrade instructions are available also in the main documentation, with some differences. I suggest eliminating redundancy, and having only one document.