HGKeeper

4ec99415f32b

Replace ioutils as it is deprecated since go 1.17

Reviewed at https://reviews.imfreedom.org/r/2444/

This documentation gets deployed to

[docs.imfreedom.org/hgkeeper](https://docs.imfreedom.org/hgkeeper/) via CI.

To build it locally it requires the

[include-markdown](https://github.com/mondeja/mkdocs-include-markdown-plugin)

plugin.