Implement API: GET /planters?keyword=[planter-name]

Be able to search planter by planter's first & last name.

Also please modify the yaml doc about this feature.

To implement an endpoint:

- Please write an e2e test to cover it.
- Please follow the guide in the 'readme' to follow our architecture on the server-side.

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Some hints:

- Please read our readme for more information/guide/tutorial.
- Here is [an engineering book](https://greenstand.gitbook.io/engineering/) in Greenstand.
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