Sorting out where the app.ini file is depending on the environment

Changed because of a script introduced in December 2021 in docker. /usr/local/bin/gitea is a script, not the binary, and sets environment variables.

The actual binary is in /app/gitea/gitea and has different default settings for where to find the work path or app.ini. For instance when calling doctor /app/gitea/gitea will fail but /usr/local/bin/gitea will work.