[Grbl_Esp32 Issue#334] Images for Wiki

This issue is a container for images used in the wiki, to work around the GitHub deficiency that images cannot be inserted directly into wiki pages, but rather must either be committed to the repository or else hosted externally. The technique of using an issue as an image container was suggested in https://ardalis.com/add-images-easily-to-github

!SerialPort

!Upload

!UploadTop

!UploadBottom

!UploadFail

!SerialMonitorMenu

!SerialMonitorStartup

!APspecs

!SerialMonitorStartupInfo