Auth: Allow expiration of API keys (#17678)

* Modify backend to allow expiration of API Keys

* Add middleware test for expired api keys

* Modify frontend to enable expiration of API Keys

* Fix frontend tests

* Fix migration and add index for `expires` field

* Add api key tests for database access

* Substitude time.Now() by a mock for test usage

* Front-end modifications

* Change input label to `Time to live`
* Change input behavior to comply with the other similar
* Add tooltip

* Modify AddApiKey api call response

Expiration should be *time.Time instead of string

* Present expiration date in the selected timezone

* Use kbn for transforming intervals to seconds

* Use `assert` library for tests

* Frontend fixes

Add checks for empty/undefined/null values

* Change expires column from datetime to integer

* Restrict api key duration input

It should be interval not number

* AddApiKey must complain if SecondsToLive is negative

* Declare ErrInvalidApiKeyExpiration

* Move configuration to auth section

* Update docs

* Eliminate alias for models in modified files

* Omit expiration from api response if empty

* Eliminate Goconvey from test file

* Fix test

Do not sleep, use mocked timeNow() instead

* Remove index for expires from api_key table

The index should be anyway on both org_id and expires fields.
However this commit eliminates completely the index for now
since not many rows are expected to be in this table.

* Use getTimeZone function

* Minor change in api key listing

The frontend should display a message instead of empty string
if the key does not expire.

pkg/setting/setting.go

@@ -259,6 +259,8 @@ type Cfg struct {
 	RemoteCacheOptions *RemoteCacheOptions
 
 	EditorsCanAdmin bool
+
+	ApiKeyMaxSecondsToLive int64
 }
 
 type CommandLineArgs struct {
@@ -795,6 +797,7 @@ func (cfg *Cfg) Load(args *CommandLineArgs) error {
 
 	LoginMaxLifetimeDays = auth.Key("login_maximum_lifetime_days").MustInt(30)
 	cfg.LoginMaxLifetimeDays = LoginMaxLifetimeDays
+	cfg.ApiKeyMaxSecondsToLive = auth.Key("api_key_max_seconds_to_live").MustInt64(-1)
 
 	cfg.TokenRotationIntervalMinutes = auth.Key("token_rotation_interval_minutes").MustInt(10)
 	if cfg.TokenRotationIntervalMinutes < 2 {