feature: Add support for using ldap primary auth method

[elimt]

• Enable LDAP authentication through TF Provider
• Enable easier LDAP authentication by automatically setting the auth_method_id for the Terraform provider if LDAP is the primary auth method or only auth method.
• Combine fields for auth_method login_name & password
• Bump up github.com/jimlambrt/gldap & github.com/hashicorp/boundary to pull in needed changes for TF changes

Using the Primary Auth Method(LDAP) in Global Scope

provider "boundary" {
  addr                            = "http://127.0.0.1:9200"
  auth_method_login_name = "myuser"
  auth_method_password   = "passpass"
}

Using the Primary Auth Method(LDAP) in a passed-in scope:

provider "boundary" {
  addr                            = "http://127.0.0.1:9200"
  auth_method_login_name = "myuser"
  auth_method_password   = "passpass"
  scope_id                        = "s_1234567890"
}

Using auth_method_id (traditional)

provider "boundary" {
  addr                            = "http://127.0.0.1:9200"
  auth_method_id                  = "ampw_1234567890"
  auth_method_login_name = "myuser"
  auth_method_password   = "passpass"
}

Considerations

password & LDAP auth methods both need a login_name & password for Terraform Provider.
Instead of having separate Terraform password_auth_method_* & ldap_auth_method_* fields that take the same information, a new auth_method_login_name& auth_method_password has been added to pass in data required by both auth methods.
password_auth_method_login_name & password_auth_method_password fields have been set to deprecated with a recommendation to use auth_method_login_name& auth_method_password fields instead.

[jimlambrt]

I think, we can remove some unused bits.

[jimlambrt]

ty!

[ddebko]

This looks great