Implementing filtered search in the log explorer
<!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION -->
*This page may contain information related to upcoming products, features and functionality.
It is important to note that the information presented is for informational purposes only, so please do not rely on the information for purchasing or planning purposes.
Just like with all projects, the items mentioned on the page are subject to change or delay, and the development, release, and timing of any products, features, or functionality remain at the sole discretion of GitLab Inc.*
<!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION -->
### Problem to solve
@ameliabauerly [commented](https://gitlab.com/gitlab-org/gitlab/issues/37425#note_253530405)
> This combination of a terminal view, filters and a search bar isn't ideal from a UX POV. While we do have searching, filtering and terminal views within our UI, there isn't any other place in the GitLab UI where they are combined in this way. Moving forward in this direction means we're failing to utilize previously refined (and researched) patterns that already exist in our UI, which places additional, unnecessary burdens on users as they work to figure out this new pattern. I also have concerns about the scalability of this view as we add in additional filtering options.
### Proposal
Implement filtered search in the terminal view
### Designs
We can achieve this by breaking up the work into a number of different iterations:
| Iteration 1: Introduce filtered search for pods | Iteration 2: Introduce namespace as a filter option | Iteration 3: Have all filters, other than time, in the search bar |
|------------------------------------|----------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------|
| |  |  |
Additional details for Iteration 1:
| Headers would need to be removed to align this page with issue and board search bars | First dropdown example | Second dropdown example |
| ------ | ------ | ------ |
|  |  | |
All three icons, pod, environment and namespace are available on [gitlab svgs](https://gitlab-org.gitlab.io/gitlab-svgs/).
### Technical Implementation
- `<gl-filtered-search>` is available in Gitlab UI. https://gitlab-org.gitlab.io/gitlab-ui/?path=/story/base-filtered-search--default
/cc @adriel, @mnohr, @akohlbecker @mrincon
epic