fix(preprod): Understand ghe.com as github_enterprise

[chromy]

To determine vcs_provider we use part of the origin of the URL:

https://github.com/foo/bar -> github
https://gitlab.com/abcdef -> gitlab

This adds special handling for github enterprize remotes. Now instead
of:

https://foo.ghe.com/foo/bar -> ghe

we end up with:

https://foo.ghe.com/foo/bar -> github_enterprise

as the backend expects.

Resolves EME-821

[linear]

EME-821 Update sentry-cli to handle GitHub Enterprise origins

[szokeasaurusrex]

lgtm!

[szokeasaurusrex]

Some optional improvements we could do here (both can wait for a separate PR):

1. We could extract "github_enterprise" to a constant.

2. We could define an enum for the supported providers, and include a fallback for unknown providers, like so:

   enum VcsProvider {
       Github,
       GithubEnterprise
       Gitlab,
       Other(String), // or &str
   }

   Then, we would return the enum from this method. We would probably need to add some serialization logic on the enum, as well as a method to convert an arbitrary string to the enum (probably a From<&str> impl works), so I guess there's some added complexity, but it would be clear what providers we support natively.