PMM-14527 Ability to have aurora specific queries.

[JiriCtvrtka]

https://jira.percona.com/browse/PMM-14527

PMM PR: percona/postgres_exporter#373

[JNKPercona]

Server docker: perconalab/pmm-server-fb:PR-4233-217fa62
Client docker: perconalab/pmm-client-fb:PR-4233-217fa62
Watchtower docker: perconalab/pmm-watchtower-fb:PR-4233-217fa62
Client tarball: https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4233-217fa62.tar.gz
Staging instance: https://pmm.cd.percona.com/job/pmm3-aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-4233-217fa62&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4233-217fa62.tar.gz

[JNKPercona]

API tests have succeded: https://pmm.cd.percona.com/job/pmm3-api-tests/5476/

[JNKPercona]

Server docker: perconalab/pmm-server-fb:PR-4233-1f6913b
Client docker: perconalab/pmm-client-fb:PR-4233-1f6913b
Watchtower docker: perconalab/pmm-watchtower-fb:PR-4233-1f6913b
Client tarball: https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4233-1f6913b.tar.gz
Staging instance: https://pmm.cd.percona.com/job/pmm3-aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-4233-1f6913b&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4233-1f6913b.tar.gz

[JNKPercona]

API tests have succeded: https://pmm.cd.percona.com/job/pmm3-api-tests/5509/