fix issue #1597: mark files being written as "active"

[facontidavide]

Suggested changes:

1. Add the suffix ".active" to SequentialWriter::format_storage_uri
2. When storage_ is closed, rename the file to remove the ".active" suffix.
3. Save the metadata when splitting. In this way all the parts but the last one are still usable in case of crash.

To address #1597 point 3 is not necessary and maybe not even desirable, so let me know what you think.

Note:

Since rcpputils::fs is not wrapping "rename", I had to use std::filesystem instead and upgrade to C++ 17.

[fujitatomoya]

@facontidavide thanks for the PR.

@MichaelOrlov are we supposed to create PR target to rolling 1st? and then backport?

[clalancette]

@MichaelOrlov are we supposed to create PR target to rolling 1st? and then backport?

Yes please. Also, we are going to run into other problems with the switch to std::filesystem on Humble (because of older GCC compilers). But let's target this to rolling first, then deal with that in the backport.

[facontidavide]

I am temporarily closing this in favor of #1672