add blog post on interactive shell and debugging build failures

[branfosj]

closes #5

This is best show with a demo and that is best done with asciinema.

[boegel]

@branfosj Can we add a small README.md in the asciinema folder, to clarify where the *.css and *.min.js come from?

I'm not sure how painful it to re-record the shell session, but if it's not too painful I would:

• start with running easybuild --version;
• also run pwd and ls after entering the debug shell, to show that we're in the build directory;

Several suggestions tackled in branfosj#1

[branfosj]

@branfosj Can we add a small README.md in the asciinema folder, to clarify where the *.css and *.min.js come from?

I'm not sure how painful it to re-record the shell session, but if it's not too painful I would:

* start with running `easybuild --version`;

* also run `pwd` and `ls` after entering the debug shell, to show that we're in the build directory;

Several suggestions tackled in branfosj#1

README.md added in the asciinema folder.

Shell session enhanced with:

• eb --version
• pwd

That PR and all suggestions done.

[boegel]

One more tiny suggestions, looks great otherwise!

[boegel]

lgtm