* 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.
