Create a table for badges in README

[Saransh-cpp]

This makes the README file a bit more organized. I did not create a new issue for this as the change was very minor, and this PR can be easily closed if the maintainers don't want this change. I can also add other badges (for instance, the communication channels) if required!

Please let me know if any changes are required!

Before:

Now:

[ViralBShah]

Thanks for the PR and welcome to the Julia project. While visually this feels nicer to the eye, the extra column headings and such are a bit distracting.

[KristofferC]

I think the header is a bit excessive, it is quite obvious that the badges represent the badges (status) and that the text represents what "type" of badge.

[oscardssmith]

I like the alignment this adds, but I agree the header seems unnecessary.

[oscardssmith]

also, just so you know, PRs never need corresponding issues.

[Saransh-cpp]

Thanks for the quick review, @ViralBShah, @KristofferC, and @oscardssmith!

it is quite obvious that the badges represent the badges

Yes, makes sense.

GitHub's markdown does not support tables without the header. I can do something like this with GitHub's markdown (notice the empty, thin header) -

Documentation	Badge
Continuous integration	Badge
Code coverage	Badge Badge

Fortunately, GitHub's markdown also supports plain HTML. The following HTML -

<table>
    <tr>
        <td>Documentation</td>
        <td>
            <a href="https://docs.julialang.org"><img src='https://img.shields.io/badge/docs-v1-blue.svg'/></a>
        </td>
    </tr>
    <tr>
        <td>Continuous integration</td>
        <td>
            <a href="https://buildkite.com/julialang/julia-master"><img src='https://badge.buildkite.com/f28e0d28b345f9fad5856ce6a8d64fffc7c70df8f4f2685cd8.svg?branch=master'/></a>
        </td>
    </tr>
    <tr>
        <td>Code coverage</td>
        <td>
            <a href="https://coveralls.io/r/JuliaLang/julia?branch=master"><img src='https://img.shields.io/coveralls/github/JuliaLang/julia/master.svg?label=coveralls'/></a> <a href="https://codecov.io/github/JuliaLang/julia?branch=master"><img src='https://img.shields.io/codecov/c/github/JuliaLang/julia/master.svg?label=codecov'/></a>
        </td>
    </tr>
</table>

Results in -

Documentation
Continuous integration
Code coverage

But initializing URLs separately, like they are done right now, does not work with HTML here.

Should I replace the markdown content with HTML, or should I leave an empty, thin (or of the same size) header?

welcome to the Julia project

Thanks! :)

also, just so you know, PRs never need corresponding issues.

Oh, I'll keep that in mind!

[ViralBShah]

Let's replace the markdown with html.

[ViralBShah]

Folks - the code coverage stuff seems quite a bit old (2 months). Should we remove? Or will these be reinstated at some point?

[DilumAluthge]

We'll be turning the code coverage Buildkite back on soon: JuliaCI/julia-buildkite#54