feat: Import custom components.[#729]

[olavoasantos]

Summary

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Docs
• Build-related changes
• Other, please describe:

If changing the UI of default theme, please provide the before/after screenshot:

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)

You have tested in the following browsers: (Providing a detailed version will be better.)

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• Firefox
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• IE

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature
• Related documents have been updated
• Related tests have been updated

To avoid wasting your time, it's best to open a feature request issue first and wait for approval before working on it.

Other information:

[ulivz]

Thanks for your work, but it has been done by a plugin and we don't plan to add it to the core. please wait for the 1.0.0.

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See feature request template: To avoid wasting your time, it's best to open a feature request issue first and wait for approval before working on it.

[olavoasantos]

Thanks for the feedback. Too bad. But, it as a good exercise for me.

Keep up the good work!