feat(cli): add server user set-password-hash command (#3974)

Objectives:
- Facilitate the generation of valid password hashes that can be used with
  the `server user --user-password` CLI command.
- Encapsulate implementation details of password hashing in
  the `user` package.

Adds a new `server user hash-password` CLI command to generate the
hash from a supplied password.

Modifies the `server user set/add --user-password-hash` CLI command
to accept the password hash generated using the `hash-password`
command.

Adds `GetNewProfile(ctx, rep, username)` helper to move implementation
details to the `user` package.

Includes CLI and unit tests.

Cleans up and removes unused functions.

cli/command_user.go

@@ -4,6 +4,7 @@ type commandServerUser struct {
 	add    commandServerUserAddSet
 	set    commandServerUserAddSet
 	delete commandServerUserDelete
+	hash   commandServerUserHashPassword
 	info   commandServerUserInfo
 	list   commandServerUserList
 }
@@ -14,6 +15,7 @@ func (c *commandServerUser) setup(svc appServices, parent commandParent) {
 	c.add.setup(svc, cmd, true)
 	c.set.setup(svc, cmd, false)
 	c.delete.setup(svc, cmd)
+	c.hash.setup(svc, cmd)
 	c.info.setup(svc, cmd)
 	c.list.setup(svc, cmd)
 }