Move the repository package under examples/repository #1069

Job	Run time
examples / root-signing (ubuntu-latest)	13s
examples / multirepo (ubuntu-latest)	14s
examples / client (ubuntu-latest)	15s
examples / repository (ubuntu-latest)	7s
examples / multirepo (macos-latest)	11s
examples / root-signing (macos-latest)	22s
examples / repository (macos-latest)	13s
examples / client (macos-latest)	10s
examples / multirepo (windows-latest)	1m 29s
examples / root-signing (windows-latest)	1m 58s
examples / repository (windows-latest)	1m 12s
examples / client (windows-latest)	1m 55s
examples / tuf-client-cli (ubuntu-latest)	22s
linting / govulncheck	18s
linting / golangci-lint	20s
examples / tuf-client-cli (macos-latest)	17s
tests / Run (ubuntu-latest)	45s
examples / tuf-client-cli (windows-latest)	1m 57s
tests / Run (macos-latest)	30s
tests / Run (windows-latest)	2m 39s
	15m 27s

Provide feedback