1.17 breaking changes episode 1: preserving a custom gitconfig

Before version 1.17, when Gitea needed to change the git configuration, it modified the $HOME/.gitconfig file. For instance it would set core.quotePath to false:

[core]
	quotePath = false

When installing Gitea from docker or rootless or even from binary this $HOME/.gitconfig file belongs to a user that is dedicated to Gitea and not used by anyone else.

However, if an Gitea installation was done differently and $HOME/.gitconfig has been customized because it is shared by a user or another application, there is a good chance that manual modifications were done such as:

[user]
	name = Jane Doe
	email = jane@doe.com

It is also possible that the file was modified manually by the Gitea admin for other reasons. In both there is a potential for breakage when upgrading to Gitea >= 1.17 because the location of the file changed. It must be moved manually to the new location as follows:

• Figure out the directory where $HOME/.gitconfig must be moved by running the doctor:

$ gitea --work-path /app/gitea -c /data/gitea/conf/app.ini doctor 
[1] Check paths and basic configuration
 - [I] Configuration File Path:    "/data/gitea/conf/app.ini"
 - [I] Repository Root Path:       "/data/git/repositories"
 - [I] Data Root Path:             "/data/gitea"
 - [I] Custom File Root Path:      "/data/gitea"
 - [I] Work directory:             "/app/gitea"
 - [I] Log Root Path:              "/data/gitea/log"
OK

• Copy the $HOME/.gitconfig file to the Repository Root Path (which is /data/git/repositories in the example above).

The reason why this breaking change was introduced is to workaround a rare problem impacting Gitea installations relying on networked volumes.