In Vim, is it possible to change the default location of the user vimrc file, i.e., from $HOME/.vimrc to some other location ?
You must start vim with the command vim -u ./path/to/your/vimrcfile
vim -u ./path/to/your/vimrcfile
vim -u NONE is a good way to start Vim without any plugin or customisation.
vim -u NONE
See :help starting.txt for more information.
:help starting.txt