fix: honor --release-name instead of generating a random release name

[somaz94]

What this PR does / why we need it:

ct install --release-name <name> was ignored. Chart.CreateInstallParams only honored the release name when the chart path resolved to . or /, and unconditionally appended a random suffix — so --release-name go-backend still produced helm install go-backend-<random> (see the reproduction in the issue). This uses the provided --release-name verbatim as the release name (Helm validates the syntax). The namespace derivation is unchanged.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #198

Special notes for your reviewer:

• New unit test TestChart_CreateInstallParams in pkg/chart/chart_test.go (fails before the fix: the release came out as simple-deployment-<random> instead of my-release).
• go test ./..., go vet ./pkg/chart/, gofmt -l, and golangci-lint run ./pkg/chart/... are all clean locally.
• Namespace behavior is intentionally unchanged: with --namespace go-backend --release-name go-backend the caller now yields helm install go-backend --namespace go-backend.

[somaz94]

Gentle ping 🙏 — green and ready for review. This makes ct install honor an explicit --release-name instead of always generating a random one (also fixes the behavior reported in helm/chart-testing-action#198). Happy to address any feedback.