Add support for keywords for datasets/discovery to improve catalog search

[slesaad]

Description

Data catalog searching searches for the keyword only in the title and description of the dataset/discovery. This limits the search capabilities because not all relevant keywords can be turned into a relevant title/description.

As @danielfdsilva noted in https://teamdsig.slack.com/archives/C03LGTM2SSH/p1684314500260489?thread_ts=1684252304.580119&cid=C03LGTM2SSH, the "keywords" property could be a solution to improve the search capability by introducing hidden "keywords" that can be specified at the time of configuring the datasets, and can be used for effective search.

An example case: Searching for "methane" in the data catalog doesn't yield any results even though we have multiple methane datasets. All the gridded EPA datasets are methane emissions.

Acceptance Criteria

• [ ] Dataset/discovery configuration should provide an option to add keywords to a dataset/discovery
• [ ] Search should also include searching in the keywords

[slesaad]

@danielfdsilva how does this look? please make changes as you see fit