readme.md: rewrote Packages section [skip ci]

[firewave]

I rewrote this so I can link to it in the initial setup documentation of the CLion plugin. It also doesn't make scene to me to maintain such generic information in external repository.

I also filed https://trac.cppcheck.net/ticket/11641 about the state of the Snap package.

On a side note I think we should remove the Japanese readmeja.md as that is not maintained by us and is most very out-of-date.

[chrchr-github]

distro it likely -> distro, it is likely
Cannonical -> Canonical

[firewave]

distro it likely -> distro, it is likely Cannonical -> Canonical

Thanks. Fixed.

[chrchr-github]

Just saw another one: respetive

[firewave]

Just saw another one: respetive

Thanks. I also turned on the spell checking in my IDE.

I also realized I forgot to remove the old contents of the section.

[firewave]

I adjusted some of the language and am now satisfied with it.