Merge branch 'configurable-disk-size' into 'master'

Make disk size configurable per image

Closes #127

See merge request !160
6 jobs for master in 35 minutes and 54 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Lint
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shellcheck

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shfmt

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  Build
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secure
build:secure

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  Test
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fast-single-thread
test-basic-qemu

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passed #15624
fast-single-thread
test-cloudimg-qemu

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passed #15622
test-vagrant-boxes-format

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