Add OAS contract monitoring support (#325)

* Add OAS contract monitoring support

* Pass the contract failure reason to UI

* Fix the issues related to contract validation

* Fix rest of the issues in the UI

* Add documentation related to contract monitoring feature

* Fix a typo in the docs

* Unmarshal to `HTTPRequestResponsePair` only if the OAS validation is enabled

* Fix an issue caused by the merge commit

* Slightly change the logic in the `validateOAS` method

Change the `contractText` value to `No Breaches` or `Breach` and make the text `white-space: nowrap`.

* Retrieve and display the failure reason for both request and response

Also display the content of the contract/OAS file in the UI.

* Display the OAS under `CONTRACT` tab with syntax highlighting

Also fix the styling in the entry feed.

* Remove `EnforcePolicyFileDeprecated` constant

* Log the other errors as well

* Get context from caller instead

* Define a type for the contract status and make its values enum-like

* Remove an unnecessary `if` statement

* Validate OAS in the CLI before passing it to Agent

* Get rid of the `github.com/ghodss/yaml` dependency in `loadOAS` by using `LoadFromData`

* Fix an artifact from the merge conflict

cli/config/configStructs/tapConfig.go

@@ -3,8 +3,9 @@ package configStructs
 import (
 	"errors"
 	"fmt"
-	"github.com/up9inc/mizu/shared/units"
 	"regexp"
+
+	"github.com/up9inc/mizu/shared/units"
 )
 
 const (
@@ -18,6 +19,7 @@ const (
 	DryRunTapName                 = "dry-run"
 	WorkspaceTapName              = "workspace"
 	EnforcePolicyFile             = "traffic-validation-file"
+	ContractFile                  = "contract"
 )
 
 type TapConfig struct {
@@ -34,6 +36,7 @@ type TapConfig struct {
 	DryRun                 bool      `yaml:"dry-run" default:"false"`
 	Workspace              string    `yaml:"workspace"`
 	EnforcePolicyFile      string    `yaml:"traffic-validation-file"`
+	ContractFile           string    `yaml:"contract"`
 	ApiServerResources     Resources `yaml:"api-server-resources"`
 	TapperResources        Resources `yaml:"tapper-resources"`
 }