feat: extend plugin API supports communication

[airslice]

close reearth/reearth#376

Overview

This PR enables plugin communication with other plugins.

What I've done

Implement the API:

type PluginExtensionInstance = {
  id: string;
  pluginId: string;
  name: string; 
  extensionId: string;
  extensionType: "widget" | "block";
};

reearth.plugins.instances: PluginExtensionInstance[]
reearth.plugins.postMessage(id: string; message: any)
reearth.on("pluginmessage", (e: { data: any, sender: string }) => {})

What I haven't done

How I tested

Test with plugin:

plugincomm.zip

Download & install & add multiple instances for test.
Also add block for test.

Screenshot

Which point I want you to review particularly

Memo

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[codecov]

Codecov Report

Merging #364 (54a852d) into main (1fcc75f) will decrease coverage by 0.07%.
The diff coverage is 1.85%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #364      +/-   ##
==========================================
- Coverage   24.61%   24.53%   -0.08%     
==========================================
  Files         596      597       +1     
  Lines       62659    62873     +214     
  Branches     1243     1243              
==========================================
+ Hits        15424    15428       +4     
- Misses      47189    47399     +210     
  Partials       46       46              

Impacted Files	Coverage Δ
...rc/components/molecules/Visualizer/Plugin/hooks.ts	3.89% <0.00%> (-0.22%)	⬇️
...rc/components/molecules/Visualizer/Plugin/types.ts	0.00% <0.00%> (ø)
src/components/molecules/Visualizer/hooks.ts	0.00% <0.00%> (ø)
src/components/molecules/Visualizer/index.tsx	0.00% <0.00%> (ø)
src/components/molecules/Visualizer/storybook.tsx	0.00% <0.00%> (ø)
...ponents/molecules/Visualizer/usePluginInstances.ts	0.00% <0.00%> (ø)
src/components/molecules/Visualizer/Plugin/api.ts	6.16% <4.16%> (-0.12%)	⬇️
...components/molecules/Visualizer/Plugin/context.tsx	32.03% <33.33%> (+0.03%)	⬆️