Adding `jldoctest` to Tutorial blocks

[pebeto]

As the title mentions, this is a need to ensure functionality checks across versions.

[pebeto]

In cfb00d6, @example and @repl macros were added to avoid defining results in Tutorial blocks. However, I'm not sure if this is exactly the same as jldoctest blocks (which stops documentation building if a check fails).

[aryawadhwa]

@pebeto Hi I looked into this , the @repl blocks in the tutorial run code during the doc build but do not verify output,
so a breaking change in the API would go unnoticed. I plan to convert the deterministic
ones (like initialize_database, create_project, create_experiment) to named
jldoctest blocks and also set doctest=true in make.jl. Let me know if this looks right.