Add template provider and converter

[djaglowski]

Example

my_template.yaml

type: my_otlp_template
template: |
  receivers:
    otlp:
      protocols:
        http:
          endpoint: localhost:{{ .port }}
  pipelines:
    traces:
      receivers: [otlp]
    metrics:
      receivers: [otlp]
    logs:
      receivers: [otlp]

config.yaml

receivers:
  template/my_otlp_template:
    port: 4317

exporters:
  logging:
    loglevel: debug

service:
  pipelines:
    logs:
      receivers: [template/my_otlp_template]
      exporters: [logging]

./otelcorecol --config config.yaml --config template:my_template.yaml

[codecov]

Codecov Report

Patch coverage is 90.66% of modified lines.

Files Changed	Coverage
otelcol/configprovider.go	33.33%
confmap/converter/templateconverter/template.go	92.03%
confmap/provider/templateprovider/provider.go	100.00%

📢 Thoughts on this report? Let us know!.

[djaglowski]

Closing in favor of #8507