[DO NOT MERGE] Add Dedicated Gateway Type

[tarazou9]

Why make this change?

To support distributed query on dedicated gateway.

What is this change?

• Add a drop down for dedicated gateway type.
• On enable dedicated gateway, user can change the value of its type.
• Once saved and enabled, the type will be disabled.
• When rendering an account with dedicated gateway already provisioned, the dedicated gateway type should reflect correct value.
• Modified the blurb on the top.
• Added tooltip for the dropdown.
  - TODO: need to update the document link in tooltip once we have it.

How was this tested?

Tested locally. Cases tested:

1. Provisioned dedicated gateway with "Distributed Query" type successfully
   • Reload page after provisioned succeeded, value retrieved correctly.
   • Once provisioned, dropdown disabled for modification.
   • Increased the instances count, succeeded upon save.
   • Deprovisioned successfully
2. Provisioned dedicated gateway with "Integrated Cache" type successfully
   • Reload page after provisioned succeeded, value retrieved correctly
   • Once provisioned, dropdown disabled for modification.
   • Increased the instances count, succeeded upon save
   • Deprovisioned successfully
3. Existing sqlx accounts
   • Show Integrated Cache as default and disabled for modification.