PMM-10180: disable http compression by default with experimental PG exporter

[ritbl]

https://jira.percona.com/browse/PMM-10180

• PMM-10180: disable http compression by default percona/pmm-managed#1157
• PMM-10180: Add DisableCompression option percona/promconfig#14
• PMM-7806: add compatibility with percona pg exporter [experimental] percona/postgres_exporter#69

contains experimental improvements:

• includes pprof
• sync scrape
• minor perf tweaks

[JNKPercona]

server docker - perconalab/pmm-server-fb:PR-2570-c993483
client docker - perconalab/pmm-client-fb:PR-2570-c993483
client - https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm2-client/pmm2-client-PR-2570-c993483.tar.gz
Create Staging Instance: https://pmm.cd.percona.com/job/aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-2570-c993483&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm2-client/pmm2-client-PR-2570-c993483.tar.gz

[JNKPercona]

API tests have failed, Please check: API: https://pmm.cd.percona.com/job/pmm2-api-tests/10300/

[JNKPercona]

pmm2-client testsuite has failed, Please check: BATS: https://pmm.cd.percona.com/job/pmm2-testsuite/9824/

[JNKPercona]

UI tests have failed, Please check: UI: https://pmm.cd.percona.com/job/pmm2-ui-tests/17096/

[JNKPercona]

Dockerway Upgrade tests have failed, Please check: Upgrade: https://pmm.cd.percona.com/job/pmm2-upgrade-tests/15595/

[JNKPercona]

server docker - perconalab/pmm-server-fb:PR-2570-d53c17a
client docker - perconalab/pmm-client-fb:PR-2570-d53c17a
client - https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm2-client/pmm2-client-PR-2570-d53c17a.tar.gz
Create Staging Instance: https://pmm.cd.percona.com/job/aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-2570-d53c17a&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm2-client/pmm2-client-PR-2570-d53c17a.tar.gz

[JNKPercona]

API tests have failed, Please check: API: https://pmm.cd.percona.com/job/pmm2-api-tests/10356/