Implement option to specify location of index files

[fridrich]

This PR implements an option "-b" for base_dir specifying location of index.html and index.js files for welle-cli web interface. It allows not to have to run the binary in the directory where those files are located.

One can test it to run it from other directory with option like for instance "-b /usr/share/welle-io/html" and the index.html and index.js files from that directory will be used.

If this option is not specified, the welle-cli behaves like before. One can test it by starting it without that option in a directory that does not have those files and then without that option in a directory that has those files.

This can be useful when debugging and the directory where the files are is read-only and the dumps go to the current directory for instance.

[fridrich]

The requirement of cmake 3.10+ and the C++17 is because I use the std::filesystem::path which requires C++17 (gcc 8+)

[mpbraendli]

Thanks!

@AlbrechtL I'm ok with the functional change, what's the impact of switching to C++17 for downstream distribution and packaging?

[fridrich]

I mean, that is possible with gcc 8. I build it with gcc 8 on SLE 12. Also the cmake 3.10 requirement is not so difficult to achieve, I guess. But the world is is now on gcc 14, so gcc 8 should be really fine. At least for me in SUSE, I am able to build it for all supported distributions.

[fridrich]

Better said, I cannot build on sle12 because of the different qt6 and mp3lame and similar, but the cmake and gcc is not a problem

[mpbraendli]

I'm not too worried about the change. I've recently moved most of the ODR-mmbTools to C++17 too.

[AlbrechtL]

@AlbrechtL I'm ok with the functional change, what's the impact of switching to C++17 for downstream distribution and packaging?

Honestly, I have no idea. But let's see..