Debian direct deb and udeb upload

What does this MR do and why?

Describe in detail what your merge request does and why.

This is item 5.3 of &6057 (comment 582697034).

How to test

• Get a private token $api_token (with API scope). Example:

  $ api_token=glpat-ABCDE

• Create a project, get the $project id. Example:

  $ project_id=28

• Define distribution variables: $codename and $suite. Example :

  $ codename=foobar
  $ suite=baz

• Enable Debian packages for the project

  Feature.enable(:debian_packages, Project.find(28)

• Create a distribution:

  $ curl --request POST --header "PRIVATE-TOKEN: $api_token" "http://localhost:3000/api/v4/projects/$project_id/debian_distributions?codename=$codename&suite=$suite"
  {"id":1,"codename":"foobar","suite":"baz","origin":null,"label":null,"version":null,"description":null,"valid_time_duration_seconds":null,"components":["main"],"architectures":["all","amd64"]}

• Upload:

  $ curl --request PUT --user "a:$api_token" "http://localhost:3000/api/v4/projects/$project_id/packages/debian/?distribution=$codename&component=main" --upload-file  spec/fixtures/packages/debian/sample-dev_1.2.3~binary_amd64.deb
  {"message":"201 Created"}

• Verify that the package is visible in the interface and available in the repository

  $ sudo mkdir -p /usr/local/share/keyrings
  $ curl --header "PRIVATE-TOKEN: $api_token" \
      "http://localhost:3000/api/v4/projects/$project_id/debian_distributions/$codename/key.asc" \
      | \
      gpg --dearmor \
      | \
      sudo tee /usr/local/share/keyrings/$codename-archive-keyring.gpg \
      > /dev/null
  $ echo "machine http://localhost:3000 login noidea password $api_token" \
     | sudo tee /etc/apt/auth.conf.d/gitlab_project.conf
  $ echo "deb [ signed-by=/usr/local/share/keyrings/$codename-archive-keyring.gpg ] http://localhost:3000/api/v4/projects/$project_id/packages/debian $codename main" \
   | sudo tee /etc/apt/sources.list.d/gitlab_project.list > /dev/null
  $ sudo apt-get update
  [snip]
  $ apt show sample-dev
  Package: sample-dev
  Version: 1.2.3~binary
  Priority: optional
  Section: libdevel
  Source: sample (1.2.3~alpha2)
  Maintainer: John Doe <john.doe@example.com>
  Installed-Size: 7 168 B
  Depends: libsample0 (= 1.2.3~binary)
  Homepage: https://gitlab.com/
  Download-Size: 1 164 B
  APT-Sources: http://localhost:3000/api/v4/projects/28/packages/debian foobar/main amd64 Packages
  Description: Some mostly empty development files
   Used in GitLab tests.
   .
   Testing another paragraph.