Change documentation to have better readibility

Change documentation of COS and cbmultimanager repo's to have better readibility.

Files to go through: (Create sub-task for each you change)

./microlith/loki/alerting/custom/README.md
./microlith/loki/alerting/couchbase/README.md
./microlith/grafana/README.md
./microlith/prometheus/alerting/generated/README.md
./microlith/prometheus/alerting/overrides/README.md
./microlith/prometheus/alerting/custom/README.md
./microlith/prometheus/alerting/couchbase/README.md
./distributed/README.md
./README.md
./testing/loki_alerts/README.md
./CONTRIBUTING.md
./examples/containers/dynamic/prometheus/custom-alertmanagers/README.md
./examples/containers/dynamic/prometheus/couchbase-servers/README.md
./examples/containers/multi/README.md
./examples/containers/README.md
./examples/kubernetes/README.md
./SECURITY.md
./upstream/cbmultimanager/ui/README.md
./upstream/cbmultimanager/cluster-monitor/README.md
./upstream/cbmultimanager/agent/README.md
./upstream/cbmultimanager/agent/pkg/hazelnut/writing-rules.md
./upstream/cbmultimanager/README.md

./upstream/cbmultimanager/CONTRIBUTING.md 

The ones which are strikethrough might not be significant. Please go through them once before ignoring them.