Make a bit better the scripts

[lvarin]

Few minor improvements of build and run script:

• Old scripts were building images with the old google server eu.gcr.io/tes-wes/$1:testing.
• Using rootless buiildah, that allows to build with older docker format (Rahti issue).
• Added possibility to change the tag.
• Fixed suggested issues by shellcheck, like the no shebang problem

[uniqueg]

Would you mind describing a bit what you did and what problem it addresses, @lvarin? :)

[lvarin]

Would you mind describing a bit what you did and what problem it addresses, @lvarin? :)

Sure, done