Remove .idea folder from git

[GeorgiiFirsov]

Solution for #22

[unterumarmung]

The idea was not only to remove .idea from git.

Making .idea version controlled is not a bad idea generally: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839-How-to-manage-projects-under-Version-Control-Systems

In this project it contains info about code style: https://github.com/unterumarmung/fixed_string/blob/master/.idea/codeStyles/Project.xml

But it's not a very convenient way to define a code style for a C++ project, because we have a lot of tools and IDEs.

Instead of CLion-based code style checking we need to provide a clang-tidy config that defined code style.

[GeorgiiFirsov]

Instead of CLion-based code style checking we need to provide a clang-tidy config that defined code style.

So this PR should be linked to #25 too. To be implemented...

[unterumarmung]

Instead of CLion-based code style checking we need to provide a clang-tidy config that defined code style.

So this PR should be linked to #25 too. To be implemented...

Not necessarily. #25 is about CI. This one is about changing a code style checks engine. But it can implemented here too.