PMM-7 Remove hardcoded datasource UUIDs

[ademidoff]

https://jira.percona.com/browse/PMM-7

• PMM-7 Replace hard-coded postgres-ds IDs percona/grafana-dashboards#1749

[JNKPercona]

Server docker: perconalab/pmm-server-fb:PR-4166-5c681cf
Client docker: perconalab/pmm-client-fb:PR-4166-5c681cf
Watchtower docker: perconalab/pmm-watchtower-fb:PR-4166-5c681cf
Client tarball: https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4166-5c681cf.tar.gz
Staging instance: https://pmm.cd.percona.com/job/pmm3-aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-4166-5c681cf&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4166-5c681cf.tar.gz

[JNKPercona]

API tests have succeded: https://pmm.cd.percona.com/job/pmm3-api-tests/4688/

[JNKPercona]

Server docker: perconalab/pmm-server-fb:PR-4166-5c681cf
Client docker: perconalab/pmm-client-fb:PR-4166-5c681cf
Watchtower docker: perconalab/pmm-watchtower-fb:PR-4166-5c681cf
Client tarball: https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4166-5c681cf.tar.gz
Staging instance: https://pmm.cd.percona.com/job/pmm3-aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-4166-5c681cf&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4166-5c681cf.tar.gz

[JNKPercona]

API tests have succeded: https://pmm.cd.percona.com/job/pmm3-api-tests/4694/

[JNKPercona]

Server docker: perconalab/pmm-server-fb:PR-4166-f1b8609
Client docker: perconalab/pmm-client-fb:PR-4166-f1b8609
Watchtower docker: perconalab/pmm-watchtower-fb:PR-4166-f1b8609
Client tarball: https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4166-f1b8609.tar.gz
Staging instance: https://pmm.cd.percona.com/job/pmm3-aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-4166-f1b8609&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4166-f1b8609.tar.gz

[JNKPercona]

API tests have succeded: https://pmm.cd.percona.com/job/pmm3-api-tests/4708/