cmd/commands: add offset and limit params to roots cmd

[guggero]

Without these parameters only the first 512 asset roots can be shown.

[coveralls]

Pull Request Test Coverage Report for Build 13371847609

Details

• 0 of 2 (0.0%) changed or added relevant lines in 1 file are covered.
• 15 unchanged lines in 6 files lost coverage.
• Overall coverage increased (+0.02%) to 41.034%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cmd/commands/universe.go	0	2	0.0%

Files with Coverage Reduction	New Missed Lines	%
asset/asset.go	2	77.65%
commitment/tap.go	2	84.32%
internal/test/helpers.go	2	86.95%
tapgarden/planter.go	2	64.98%
tapchannel/aux_leaf_signer.go	3	43.43%
tapgarden/caretaker.go	4	68.11%

Totals
Change from base Build 13371806865:	0.02%
Covered Lines:	27340
Relevant Lines:	66628

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💛 - Coveralls

[GeorgeTsagk]

Lgtm, ty!