Documentation of `eo` objects in `xmir` strucure

[levBagryansky]

Now documentation for the structure of eo objects in xmiris contained in the article. But there is no information about optimized xmir. For example it is not clear what abstract or probe mean. I think we need to extend documentation. @yegor256 @c71n93 @MikhailLipanin WDYT?

[c71n93]

@yegor256 @levBagryansky I also faced the problem of a lack of documentation on xmir. I think it is also necessary to update and expand the documentation on non-optimized xmir. Because the information in the article is outdated.

[yegor256]

@volodya-lombrozo can you try to add the missing parts to the blog post? I'm talking about probe only for now.