Add mise support to geo installer

Overview

After mise support was added to the GDK's main installer, the geo installer is not broken. The same support to choose between asdf and mise needs to be added in order to make geo-install usable again

Impacted categories

The following categories relate to this issue:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Steps to replicate (optional)

Run the Geo installer for 2 sites described here, and the installation will stop with:

INFO: Bootstrap successful!
bash: line 135: gdk: command not found

Proposal (optional)

The same mise support added to the regular installer should be added to geo-install.