Fix system environment detection

fix: create path dependencies relative to package rather than lockfile (#4245)

* update shell command 

according to [SC2006](https://github.com/koalaman/shellcheck/wiki/SC2006):
> Backtick command substitution `...` is legacy syntax with several issues.

* merge updated table markdown

fixed broken link

Dependency groups

Properly detect if packages are a git installation over directory installation

Resolution speed improvement

Fix warning about  self update when using install-poetry.py

Relates-to: #2899

* handle poetry init non-interactive dependencies

1. in non-interactive mode, suppress "This command will guide you through..."
2. in interactive mode, respect command line --dependency if the user chooses NO for "Would you like to define your main dependencies interactively?"

Fix locked information for path, url and VCS dependencies

Fix documentation relative reference

Reorganize documentation

replace f-string in get-poetry by `.format()` for python2 compatibility

Relates-to: #4040

When installing poetry < 1.2.0a1 add a warning indicating the breakage
of `self update` command usage.

Relates-to: #4040

Relates-to: #4040

Release 1.2.0a1

Improve the `self update` command to account for the new installer