enhancement(apt platform,debian platform,dpkg platform,centos platform,rhel platform,rpm platform,yum platform): Improve packaging and service best practices (#13456)

* feat(apt platform,debian platform,dpkg platform): Misc deb improvements (#12573)

* chore(apt platform,debian platform,dpkg platform): remove daemon-reloads as service hasn't been installed

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* feat(apt platform,debian platform,dpkg platform): Do all setup in preinst and only when configuring

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* back to postinst, set permissions on vector directories and files per target spec

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* add comments to chown/chmod commands

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* feat(centos platform,rhel platform,rpm platform,yum platform): Match deb permissions and groups to rpm (#12593)

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* enhancement(config): Change default config to aggregator and convert defaults back to toml

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* chore: Remove accidentally committed service files

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* improve best practices in service file and update rpm and dep accordingly

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* remove stray env file reference in postinst

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* fix rpmbuild error due to missing files

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* fix hardened service

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* update config/vector.toml and config/aggregator/vector.toml

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* +pr feedback

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* +fix check

* use install command in postinst

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>

* move default configs into examples

Signed-off-by: Spencer Gilbert <spencer.gilbert@datadoghq.com>