Fixes #2536
Signed-off-by: NJeroen van Baarsen <jeroenvanbaarsen@gmail.com>

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

and request them each session. Pass these tokens to the project import data.

This prevents the need to encrypt these tokens and clear them in case they
expire or get revoked.

For example, if you deleted and re-created OAuth2 keys for Bitbucket, you would get
an Error 500 with no way to recover:

```
Started GET "/import/bitbucket/status" for x.x.x.x at 2015-08-07 05:24:10 +0000
Processing by Import::BitbucketController#status as HTML
Completed 500 Internal Server Error in 607ms (ActiveRecord: 2.3ms)

NameError (uninitialized constant Import::BitbucketController::Unauthorized):
  app/controllers/import/bitbucket_controller.rb:77:in `rescue in go_to_bitbucket_for_permissions'
  app/controllers/import/bitbucket_controller.rb:74:in `go_to_bitbucket_for_permissions'
  app/controllers/import/bitbucket_controller.rb:86:in `bitbucket_unauthorized'
```

Closes #1871

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Closes #1798

delay is in seconds
more legible code in session_store
Added `GitLab restart required` help block to session_expire_delay

settings

Closes https://github.com/gitlabhq/gitlabhq/issues/6745

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

This feature was requested long ago:

http://feedback.gitlab.com/forums/176466-general/suggestions/4118466-ability-to-register-only-from-ceratain-domains

This MR is based off !253 but changed to use application settings and use wildcard strings
to give more flexibility in pattern matching. Regexps seemed overkill and easy to get wrong.

Only restrict e-mail addresses upon creation

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Upon tagging a repository, an error due to a missing migration occurred:

```
    PG::Error: ERROR:  column "taggings_count" does not exist
        LINE 1: UPDATE "tags" SET "taggings_count" = COALESCE("taggings_coun...
```

Ran `rake acts_as_taggable_on_engine:install:migrations`, removed the first
migration that created the `tags` and `taggings` table, and added the rest.

Closes #1512
Closes https://github.com/gitlabhq/gitlabhq/issues/6867
Closes https://github.com/gitlabhq/gitlabhq/issues/9194

Add new global application settings for default project and snippet
visibility levels.