noahdarveau/Rollup changes for treeshaking

[noahdarveau-MSFT]

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Description

Summarize the changes, including the goals and reasons for this change. Be sure to call out any technical or behavior changes that reviewers should be aware of.

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Main changes in the PR:

1. Added Rollup to the repository which will be used to build a treeshakable version of Teams-JS once the treeshaking code changes go in.
2. Changed the pkg.json file to have the main field point to the minified cdn bundle and added the module field to point to the esm bundle.
3. Added a basic tree shaking test app that was used to verify tree shaking is working in teams-js. Note that there are no automated tests to check if tree shaking is working.

Validation

Validation performed:

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Unit Tests added:

Unit tests are required for all changes. If no unit tests were added as part of this change, please explain why they aren't necessary.

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End-to-end tests added:

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Additional Requirements

Change file added:

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Related PRs:

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Next/remaining steps:

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• Item 1
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Screenshots:

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Before	After
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