Add section comparing `ubi` to `curl ... | sh` #723

Job	Run time
Linux - bootstrap-ubi.sh - no tag	4s
Linux - bootstrap-ubi.sh - v0.1.1	2s
Alpine Linux (ash) - bootstrap-ubi.sh - no tag	16s
Alpine Linux (ash) - bootstrap-ubi.sh - v0.1.1	7s
macOS - bootstrap-ubi.sh - no tag	6s
macOS - bootstrap-ubi.sh - v0.1.1	5s
Windows - bootstrap-ubi.ps1 - no tag	15s
	55s

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