Add tmp volume

[pschumacher]

The Chromium module needs to be able to write to the /tmp directory of the container. When running the container with a read-only filesystem (securityContext.readOnlyRootFilesystem), this leads to the following Gotenberg error:

create request context: create working directory: create directory /tmp/6035cd1c-8e13-4e53-a871-c4c56d3e04bc: mkdir /tmp/6035cd1c-8e13-4e53-a871-c4c56d3e04bc: read-only file system

In oder to support running a read-only filesystem, it should be possible to configure a volume that is mounted at /tmp.

Tasks:

• [ x ] I've made changes
• [ x ] I've bumped chart's version in Chart.yaml
• [ x ] I've added changes to charts CHANGELOG.md
• [ x ] I've run helm-docs

[MaikuMori]

Hi, I'll review this shortly. Overall looks ok.

[MaikuMori]

My only concern is the default volume.

This is because now by default we're allocating up to 2Gb extra memory on the node. I would prefer to just comment the default volume out and leave it as an example for whomever needs it as a template.

An alternative would be to place it behind a flag.

What do you think?

[pschumacher]

Sounds good. I have commented the default volume out and added the option to define volumeMounts.

[MaikuMori]

Thanks for the PR. I think read-only rootfs is definitely the way to go. Maybe it should be supported more explicitly among other hardening settings in the future.