Use `pwd -P` to resolve any symlinks in the current directory path.
This makes the behavior in the shell script similar to the idf_tools.py
code, which calls `os.path.realpath()`. Without this, multiple entries
can get created in the `idfInstalled` dictionary in idf-env.json, and
the installed targets and features are not fully present in all entries.
This results in a broken installation, where `export.sh` cannot set up
the environment correctly afterwards.
Allow user to select specific ESP_TARGET while setting up ESD_IDF.
Only necessary tools for given target will be downloaded and installed.
Closes https://github.com/espressif/esp-idf/issues/5113
Marek Fiala