feat: Add move_semantics5 exercise.

[sateeshkumarb]

• Added an exercise for move_semantics which helps in improving the understanding of mutable references.
• Added an exercise for option which helps in understanding of usage of keyword ref

[sateeshkumarb]

@fmoko Now that this PR is approved can you please merge this change. Or are there any additional steps I need to take for this PR to be merged. Thanks.

[shadows-withal]

@all-contributors please add @sateeshkumarb for code and content

[allcontributors]

@fmoko

I've put up a pull request to add @sateeshkumarb! 🎉

[milesfrain]

My first instinct was to solve this with & instead of the ref keyword, which worked:

    match &y {
        Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),

I assume this is the intended solution:

    match y {
        Some(ref p) => println!("Co-ordinates are {},{} ", p.x, p.y),

I'm still hazy on the difference between & vs ref, even after reading https://doc.rust-lang.org/std/keyword.ref.html#-vs-ref

Wondering if this exercise could be made more restrictive to force the ref solution.

[sateeshkumarb]

@milesfrain That is a good point and after your comment I did searched around and experimented but I couldn't come up with a way to make this exercise to be restrictive to force ref solution. Thanks for pointing this out.