Model 5 update

Adds detection of 2 off Model 5 boards.
Minor amendments to raspi-boards.txt file

Maintenance release

The following amendments were made to this release:
Amended script to remove unusued variable
Amended raspi-boards.txt to correct revision information for one board

• Thanks Max Peal for both items.

Updated 2021 Q4 boards list

Release includes all rolled up board amendmentrs and updated to documentation.
Most notably addition of:
Compute Module 4
Pi Zero 2 W

Updated 2020 Boards List For Jan 2021

Release includes latest boards released in Q4 2020 including PI 400

Notes
Summary
Issue identified with github web based editor ignoring TAB character when editing a text file, work around implemented.

Detail
Updated format of raspi-boards.txt as github ignores TAB character entered into web based editor. Though github editor respected TAB characters pasted into the editor. This resulted in the previous 1.2.0 to 1.3.1 amendments not having the correct format in the raspi-boards.txt file. The work around consists of either:

1. Pasting suitable format data into the file being edited
   or
2. Uploading a suitabale format file into github

Option 1 was applied in this instance.