Convert RestClient to Gitlab::HTTP for Prometheus Monitor

- Closes #60024

- Change PrometheusClient.new to accept a base url instead of an
  already created RestClient

- Use Gitlab::HTTP in PrometheusClient instead of creating RestClient
  in PrometheusService

- Move http_options from PrometheusService to
  PrometheusClient (follow_redirects: false)

- ensure that base urls don't have the trailing slash

- Created a `PrometheusClient#url` method that might not be strictly
  required

- Change rescued exceptions from RestClient::* to
  HTTParty::ResponseError where possible and StandardError for the
  rest

1 files changed, 4 insertions, 0 deletions

diff --git a/spec/support/matchers/be_url.rb b/spec/support/matchers/be_url.rb
index 7bd0e7fada4..69171f53891 100644
--- a/spec/support/matchers/be_url.rb
+++ b/spec/support/matchers/be_url.rb
@@ -5,3 +5,7 @@ RSpec::Matchers.define :be_url do |_|
     URI.parse(actual) rescue false
   end
 end
+
+# looks better when used like:
+#   expect(thing).to receive(:method).with(a_valid_url)
+RSpec::Matchers.alias_matcher :a_valid_url, :be_url