Add peer selection display example

[easylogic]

What this PR does / why we need it?

Allows selection information from the yorkie.Tree to be sent remotely.
support remote selection viewer.

Any background context you want to provide?

Tree selection information is provided by the createRange () function.

const selection = root.tree.createRange(fromIndex, toIndex);

The selection is converted to a string for transmission to the remote.

root.tree.createRange(from, to).map((it) => {
      return yorkie.converter.toHexString(
            yorkie.converter.objectToBytes(
              yorkie.Primitive.of(it.offset, it.createdAt),
            ),
     );
});

As you can see in the code, there is no way to simply send pos, so we wrap it in Primitive.of.
The reason for this is so that we can transform it into bytes and send it.

The converted selection information is then sent via root.selection to root.tree in the same way as root.tree.

root.selection = root.tree.createRange().map( () => {
    .....
});

There's a problem: the selection information is an array, which generates quite a few operations.

Set, Add, Add

At least three things must be done, because range information has from and to.

2023-06-14.5.17.30.mov

What are the relevant tickets?

Fixes #543

Checklist

• Added relevant tests or not required
• Didn't break anything

[codecov]

Codecov Report

Merging #544 (63ed1c6) into main (9f6e51b) will decrease coverage by 0.25%.
The diff coverage is 46.87%.

@@            Coverage Diff             @@
##             main     #544      +/-   ##
==========================================
- Coverage   87.99%   87.75%   -0.25%     
==========================================
  Files          77       77              
  Lines        7372     7464      +92     
  Branches      712      731      +19     
==========================================
+ Hits         6487     6550      +63     
- Misses        612      630      +18     
- Partials      273      284      +11     

Impacted Files	Coverage Δ
src/api/converter.ts	91.04% <0.00%> (-0.99%)	⬇️
src/document/json/tree.ts	54.44% <0.00%> (-6.05%)	⬇️
src/yorkie.ts	100.00% <ø> (ø)
src/document/crdt/tree.ts	82.95% <50.00%> (-1.17%)	⬇️
test/unit/document/crdt/tree_test.ts	74.20% <100.00%> (+1.02%)	⬆️

... and 5 files with indirect coverage changes

[hackerwins]

Thanks for your contribution.