Start with iid on branch creation

After the discussion it in #3886 it was decided the iid should be in the beginning of the branch name.

See merge request !3708

Refactor and expose only Gitlab::UrlBuilder.build(record)

```
$ git grep Gitlab::UrlBuilder

app/models/commit.rb:      url: Gitlab::UrlBuilder.build(self),
app/services/issues/base_service.rb:      issue_url = Gitlab::UrlBuilder.build(issue)
app/services/merge_requests/base_service.rb:      hook_data[:object_attributes][:url] = Gitlab::UrlBuilder.build(merge_request)
app/views/search/results/_note.html.haml:- note_url = Gitlab::UrlBuilder.build(note)
lib/gitlab/note_data_builder.rb:        base_data[:object_attributes][:url] = Gitlab::UrlBuilder.build(note)
spec/lib/gitlab/note_data_builder_spec.rb:    expect(data[:object_attributes][:url]).to eq(Gitlab::UrlBuilder.build(note))
spec/lib/gitlab/url_builder_spec.rb:describe Gitlab::UrlBuilder, lib: true do
```

Fixes #15202.

See merge request !3696

Closes #13574

Fix a bug with trailing slash in bamboo_url

Also, improve specs for BambooService

Similar to !3679.

See merge request !3680

Fix trailing slash in teamcity_url

Originally opened at !2309 by @ctmay4.

As described in #3515, if you have trailing spaces in the the Teamcity server name, the service
will not work properly.  Switching from `URI.parse` to `URI.join` fixes it so that it works with
or without a trailing slash.

Fixes #3515.

See merge request !3679

Signed-off-by: Rémy Coutable <remy@rymai.me>

Also, improve specs for BambooService

Similar to https://gitlab.com/gitlab-org/gitlab-ce/issues/3515

Signed-off-by: Rémy Coutable <remy@rymai.me>

Allow to close invalid merge request

fixes #15044

See merge request !3664

Signed-off-by: Rémy Coutable <remy@rymai.me>