This reverts commit b0498c17

This regexp is extracted from Docker Distribution 2.4.1 docs, contains
additional `/` element that can be a separator of components.

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>

Javascript does not support the negative lookbehind assertion (?<!) used
in the Ruby regex (to disallow usernames ending in `.git` or `.atom`.

Getting the client side code to fully support this format is
non-trivial, since we'd either have to heavily complicate the
regex used, or modify the frontend code to support more complex
validation schemes (it currently uses HTML5 validations).

The pragmatic choice is to create a
`Gitlab::Regex::NAMESPACE_REGEX_STR_SIMPLE` regex to serve as a
Javascript-compatible version of `NAMESPACE_REGEX_STR`.

The client-side code will not display an error for usernames ending in
`.git` and `.atom`, but these will be caught by the server-side
validation.

Added ability to put emojis into repository name

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

Adds .git and .atom to the master namespace regex
Updates existing group tests and adds two new ones
Updates path cleaning to also forbid .atom

Squashed commits:
[f9a9315] Use : to test invalid environment name

Environments that can have a URL with predefined CI variables.

This reverts commit 13e37a3e.

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

Simply type a name with a `/` directory separator and new directories
will be created. This does not do the fancy UI work that github.com
does, but it will get the job done.

I could not find tests for file creation, so I didn't add a test for
this slight behaviour modification. I did test directory traversals
though, using both absolute paths like `/tmp/foo.txt` and relative paths
like `../../foo.txt`. Neither case escaped the repository, though
attempting to traverse with a relative path resulted in a 500 error that
did not affect application stability upon reload.

This reverts commit c0116926.

This reverts commit c75c6b84.