update install guide platform for release 2.1

What this MR does / why we need it:

Update systems table for installation guide

Steps to complete before submitting MR:

• I have read Contribution guidelines

Release Notes

N/A

Changelog

• doc(install guide): update system table to reflect changes to e31x and plutosdr platforms and tools

Which issue(s) this MR closes

Closes #1934 (closed)