docs: add migration docs (#560) #34

Job	Run time
Review / Codegen	30s
Review / Lint ESLint	32s
Review / Build Library	35s
Review / Lint TSC	43s
Review / Test	37s
Review / Android / Build old Arch	1m 53s
Review / Android / Build new Arch	5m 57s
Review / iOS / Build old Arch	6m 0s
Review / iOS / Build new Arch	7m 32s
Review / Android / Test old Arch	3m 12s
Review / Android / Test new Arch	3m 48s
Review / iOS / Test old Arch	4m 26s
Review / iOS / Test new Arch	10m 36s
Release	1m 46s
	48m 7s

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