Rename SaaS runner group and category to Hosted runners

Context

With the recent change to move away from SaaS naming and differentiated to GitLab.com & GitLab Dedicated, we want also to rename SaaS runners, to be more clear about who can use the product.

For more information check the rename issue Rename SaaS runners to Hosted runners (Product#13113 - closed) • Fiona Neill, Rebecca Clayman+

Approvals

Merge requests with changes to stages and groups and significant changes to categories need to be created, approved, and/or merged by each of the below:

• Chief Product Officer @david (post MR link in chief-product-officer once all others have approved)
• PLT Leader relevant to the affected Section(s) @mflouton
• The Product Director relevant to the affected Section(s)
• The Engineering Director relevant to the affected Section(s) @sgoldstein
• Director of Product Design @vkarnes

Note: Chief Product Officer approval should be requested once all other approvals have been completed. To request approval, post the MR link in the #chief-product-officer channel tagging @david and cc'ing @Gena Schwam.

The following people need to be on the merge request so they stay informed:

• Chief Technology Officer @joergheilig
• Development Leader relevant to the affected Section(s) @meks
• VP of Infrastructure & Quality Engineering @meks
• VP of UX @david (Acting VP of UX leader)
• Director of Technical Writing @susantacker
• Engineering Productivity @gl-quality/eng-prod
• The Product Marketing Manager relevant to the stage group(s) @danielhom @rclayman

After Approvals and Merge

• Create an issue in the gitlab-org/quality/triage-ops project to update GitLab Bot automation:
  • for Category change
  • for Stage or Group change
  • If label migration is required, please follow the self-serve instructions to get started on a one-off label migration MR
• Open an MR in the gitlab-org/gitlab project to update any reference of the previous group label to the new one
• Mention the product group Technical Writer to update the documentation metadata
• Share MR in #product, #development, and relevant #s_, #g_, and #f_ Slack channels