Related (coderd): #8367
Related (issue): #6828

This PR added support for ephemeral parameters, so now we have add logic to handle them on the UI level.

data "coder_parameter" "force-rebuild" {
  name         = "force-rebuild"
  type           = "bool"
  display_name = "Force rebuild"
  description  = "Rebuild the project code"
  default        = "false"
  mutable      = true
  ephemeral   = true
}

Requirements:

• Start with options button or menu item which shows a popup with ephemeral parameters. Menu action should be visible only if there are any ephemeral parameters
• Settings > Parameters - show ephemeral parameters in the new section (Build options?), after Immutable parameters. The site should render the section with default values for ephemeral params. It will be perfect if the site skips submitting ephemeral parameters with default values (coderd can handle this).

I'm not sure about the 2nd requirement, but we need to support somehow this permutation: ephemeral = true and required = true.

Sample permutations to check:

• ephemeral = true and required = true (no default) - coderd will require the parameter to be present in every workspace build request, but will not persist its value between consecutive builds (definition of ephemeral)
• ephemeral = true and default = "" (empty string) - user can leave this field empty
• ephemeral = true and default = "abced"

In the meantime, I'm going to work on adjusting the CLI.