vmagent: added remoteWrite param as a replacement for remoteWriteUrls

[AndrewChubatiuk]

removed multiTenantUrls as it's deprecated in VictoriaMetrics 1.102.0
added remoteWrite param, which replaces remoteWriteUrlsand besides addingremoteWrite.* prefixed cmd flags to vmagent process also generates config map with content of values if values types are array or map. e.g:

remoteWrite:
 - url: http://localhost/api/v1/write
   urlRelabelConfig:
    - action: keep
      source_labels: [env]
      regex: "dev"

--remoteWrite.url=http://localhost/api/v1/write and --remoteWrite.urlRelabelConfig=/config/rw/0-urlRelabelConfig.yaml flags will be added together with config map, which contains

data:
  0-urlRelabelConfig.yaml: |
     - action: keep
       source_labels: [env]
       regex: "dev"

which is mounted to a pod