Add the ability to use `G` (GiB) and `T` (TiB) suffixes in configuration...

Add the ability to use `G` (GiB) and `T` (TiB) suffixes in configuration options that refer to numbers of bytes. (#16219)

* Add more suffixes to `parse_size`

* Newsfile

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

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Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>