docs: add migration docs #7242

Job	Run time
branch_name	5s
test / Run Unit Tests	4m 21s
test / Build ev-node EVM Single Docker Image	14m 38s
test / Build All ev-node Binaries	1m 58s
test / Build ev-node Docker Image	15m 10s
test / Run Integration Tests	1m 51s
test / Go Mod Tidy Check	57s
lint / golangci-lint	13s
lint / markdown-lint	1m 37s
lint / yamllint	17s
proto / buf-check	7s
lint / goreleaser-check	5s
lint / hadolint / hadolint	10s
test / Run EVM Execution Tests	2m 30s
test / Run E2E System Tests	7m 12s
test / Combine and Upload Coverage	0s
test / Docker E2E Tests	26s
release	0s
	51m 37s

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