PMM-12913 Migrate api endpoints to REST #11597

Job	Run time
Tests (mysql:5.6, mongo:4.4, postgres:10, perconalab/pmm-server:3-dev-latest)	3m 54s
Tests (mysql:5.7, mongo:4.4, postgres:11, perconalab/pmm-server:3-dev-latest)	4m 19s
Tests (mysql:8.0, mongo:4.4, postgres:12, perconalab/pmm-server:3-dev-latest)	3m 59s
Tests (mysql:8.0, mongo:4.4, postgres:13, perconalab/pmm-server:3-dev-latest)	4m 21s
Tests (percona:5.6, percona/percona-server-mongodb:4.4, perconalab/percona-distribution-postgresq...	4m 9s
Tests (percona:5.7, percona/percona-server-mongodb:4.4, perconalab/percona-distribution-postgresq...	4m 13s
Tests (percona:8.0, percona/percona-server-mongodb:4.4, perconalab/percona-distribution-postgresq...	4m 23s
Tests (mariadb:10.2, mongo:4.4, postgres:9.4, perconalab/pmm-server:3-dev-latest)	3m 55s
Tests (mariadb:10.3, percona/percona-server-mongodb:4.4, postgres:9.5, perconalab/pmm-server:3-de...	4m 10s
Tests (mariadb:10.4, postgres:9.6, perconalab/pmm-server:3-dev-latest)	4m 1s
	41m 24s

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