Place apt repo credentials to auth.conf

apt_source.sh script places credentials to sources.list file. This will cause apt to generate a warning message everytime said repository is hit.

(N: Usage of apt_auth.conf(5) should be preferred over embedding login information directly in sources.list(5) entry for 'https://.......')

This change will automatically seperate credentials from sources.list file to auth.conf file

This change was cherry picked from GitLab repository https://gitlab.apertis.org/infrastructure/apertis-image-recipes from commit aa830587d5f2ed8e0cb62b040a2143fa18668315.

Signed-off-by: Komurcu Levent levent.komurcu@nl.bosch.com (cherry picked from commit aa830587d5f2ed8e0cb62b040a2143fa18668315)