Writable deploy keys (closes #671) (#3225)

* Add is_writable checkbox to deploy keys interface

* Add writable key option to deploy key form

* Add support for writable ssh keys in the interface

* Rename IsWritable to ReadOnly

* Test: create read-only and read-write deploy keys via api

* Add DeployKey access mode migration

* Update gitea sdk via govendor

* Fix deploykey migration

* Add unittests for writable deploy keys

* Move template text to locale

* Remove implicit column update

* Remove duplicate locales

* Replace ReadOnly field with IsReadOnly method

* Fix deploy_keys related integration test

* Rename v54 migration with v55

* Fix migration hell

vendor/vendor.json

@@ -9,10 +9,10 @@
 			"revisionTime": "2017-12-22T02:43:26Z"
 		},
 		{
-			"checksumSHA1": "QQ7g7B9+EIzGjO14KCGEs9TNEzM=",
+			"checksumSHA1": "Qtq0kW+BnpYMOriaoCjMa86WGG8=",
 			"path": "code.gitea.io/sdk/gitea",
-			"revision": "ec7d3af43b598c1a3f2cb12f633b9625649d8e54",
-			"revisionTime": "2017-11-28T12:30:39Z"
+			"revision": "79eee8f12c7fc1cc5b802c5cdc5b494ef3733866",
+			"revisionTime": "2017-12-20T06:57:50Z"
 		},
 		{
 			"checksumSHA1": "bOODD4Gbw3GfcuQPU2dI40crxxk=",