Incorporate `soroban-spec-tools` dependency and remove all Soroban CLI references #87

Job	Run time
Build (ubuntu-latest, x86_64-unknown-linux-gnu, amd64)	2m 31s
Integration tests (ubuntu-20.04, 1.21, .CLI.)	2m 54s
Build (ubuntu-latest, aarch64-unknown-linux-gnu, arm64)	2m 49s
Integration tests (ubuntu-20.04, 1.21, ^Test(([^C])\|(C[^L])\|(CL[^I])).*$)	12m 49s
Unit tests (ubuntu-20.04, 1.21)	2m 51s
Integration tests (ubuntu-22.04, 1.21, .CLI.)	2m 48s
Unit tests (ubuntu-22.04, 1.21)	2m 30s
Integration tests (ubuntu-22.04, 1.21, ^Test(([^C])\|(C[^L])\|(CL[^I])).*$)	12m 12s
Build (macos-latest, x86_64-apple-darwin, amd64)	3m 47s
Build (macos-latest, aarch64-apple-darwin, arm64)	3m 39s
Build (windows-latest, x86_64-pc-windows-gnu, amd64)	6m 58s
	55m 48s

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