main/bluez: allow to pass args to service

Configuring BlueZ using main.conf requires to disable the
'hostname' plugin using --noplugin=hostname. Allow users
to provide a way to supply their own arguments to the service.
8 jobs for !22208 with bluetooth-obexd in 3 minutes and 39 seconds (queued for 3 seconds)
detached
Status Job ID Name Coverage
  Lint
passed #412235
docker-alpine x86_64
lint

00:00:13

 
  Build
passed #412240
docker-alpine ci-build aarch64
build-aarch64

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passed #412242
docker-alpine ci-build armhf
build-armhf

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passed #412241
docker-alpine ci-build armv7
build-armv7

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passed #412239
docker-alpine ci-build ppc64le
build-ppc64le

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passed #412238
docker-alpine ci-build s390x
build-s390x

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passed #412237
docker-alpine ci-build x86
build-x86

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passed #412236
docker-alpine ci-build x86_64
build-x86_64

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