Implement Slack command to trigger Analytics integration for a specific site (SITES-20863)

[iuliag]

Is your feature request related to a problem? Please describe.
Customer wants to integrate Analytics (AA, CJA) for a specific site.

Describe the solution you'd like
Add Slack command:

Integrate Analytics
Usage: integrate analytics {site}
Integrate analytics for a previously added site

That will return a link to the UI where the customer can consent to the proposed analytics implementation and trigger it.
The link needs to have the following query params set with values specific for the site:

• siteId
• gitHubURL
• baseURL
  The link to the UI needs to be configurable globally.

Describe alternatives you've considered
Manually offering the parametrized link to the customer