[FEATURE] Add filedate to VCF file

[Irallia]

This PR is a suggestion to add the filedate to the vcf. I have not yet customized the bcf tests. (I also haven't figured out how yet).
There is no regulation about the format of the filedate, so I decided to use a readable format like ##fileDate=2022-03-02 14:18:22.

[h-2]

I like some of this, but I want to have a think about the general direction before progressing with this.

If file_date is important for you, I would propose to make a PR that just adds the member variable (empty by default) and nothing else. We could merge that right away, so you can set the string from your application?

Or we just keep this as a draft for now?

[h-2]

Having file_date as an extra member seems like a good thing! However, I am not sure if I want it to be set automatically, because this results in output not being reproducible by default, which is really annoying when you are checking whether output has changed or not.

Related to this question is also whether BIO should add a line that says that the file was created with BIO. On the one hand, I would like this (advertising for the library); on the other hand, I am often annoyed by bcftools adding so many of those lines.

[Irallia]

So another solution would be to add a field which will be set by the user, e.g. the transTime() function would move to iGenVar. Would also be fine for me.

To your related question, I understand the desire to promote the library, but the important question should be whether it helps the user. At first I thought no, because why do I need to know who created it, since I am interested in the results from the tool itself. But then I thought if I don't understand a VCF line or there are errors in it (something like that) I might want to contact BIO instead of the tool creator that just uses the library. Hmm...

[h-2]

This function seems a little bit out-of-place here, because it is a generic "make a nice date"-function and not specific

I am also not sure what the name implies? 🏳️‍⚧️ 🕐 ? 😉

[Irallia]

Oh that was just a name copy of some funktions I found in the wild wild web.. 🙈 If we ceep the function, we can of course rename it to transformTime for example.

[h-2]

Also regarding any future PRs:

This library has automatic code-formatting. You can cmake the tests/format folder and then run make check_library to check if your formatting is correct or make format_library to reformat the files to correct formatting, so you don't have to worry about any style-things.

[Irallia]

I like some of this, but I want to have a think about the general direction before progressing with this.

If file_date is important for you, I would propose to make a PR that just adds the member variable (empty by default) and nothing else. We could merge that right away, so you can set the string from your application?

Or we just keep this as a draft for now?

Since it's not a super important change for me, but rather a future wish, both options are okay for me.