Piccolo-admin

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Added translations for simplified Chinese characters (courtesy mnixry).

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The media endpoints now obey the ``read_only`` option of ``create_admin``.
Read only mode is used for online demos.

Thanks to sinisaos for adding this.

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Added media upload support - to both a local folder, and S3.

Images, videos, PDFs, and audio files can be viewed within the UI.

This is the one of the biggest updates we've ever made!

Thanks to sinisaos for all of the help.

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Added Ukrainian translations (courtesy ruslan-rv-ua).

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Added Russian translations (courtesy northpowered).

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Modified the release process, so it works on GitHub (courtesy olliglorioso).

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