Project level VSA summary endpoint

What does this MR do?

This MR exposes the summary endpoint for project-level VSA.

• Project-level VSA: currently FOSS feature (legacy)
• Group-level VSA: premium feature with more functionality

We're slowly updating the project-level VSA to have the same functionality as the group-level VSA so we can share the frontend code. We intend to keep the FOSS functionality and extend the endpoint with more features (EE, premium).

The MR does the following:

• Expose the summary JSON in a separate endpoint like in the group-level VSA
  • Legacy endpoint: https://gitlab.com/gitlab-org/gitlab/-/value_stream_analytics?cycle_analytics[start_date]=30
  • New endpoint: https://gitlab.com/gitlab-org/gitlab/-/analytics/value_stream_analytics/summary.json
  • Group level endpoint with the same structure: https://gitlab.com/groups/gitlab-org/-/analytics/value_stream_analytics/summary.json
• Accept filter params to filter the summary counts (author_username, labels etc.) EE, premium only.
  • Example: https://gitlab.com/gitlab-org/gitlab/-/analytics/value_stream_analytics/summary.json&author_username=foo
• Modify the low-level finders to accept more parameters: instead of from:, to: we use options:

Note: the change is not user-facing yet. FE work is ongoing.

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #327570 (closed)