http://localhost should be allowed by @microsoft/sdl/no-insecure-url

[jason-ha]

http://localhost is common for some testing scenarios and situations where communication does not leave the OS are not a risk.

To Reproduce
Steps to reproduce the behavior:

1. Add 'http://localhost' use in code.
2. Enable recommended configuration.
3. Run eslint
4. See report similar to:

Error @microsoft/sdl/no-insecure-url: Insecure protocols such as [HTTP](https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol) or [FTP](https://en.wikipedia.org/wiki/File_Transfer_Protocol) should be replaced by their encrypted counterparts ([HTTPS](https://en.wikipedia.org/wiki/HTTPS), [FTPS](https://en.wikipedia.org/wiki/FTPS)) to avoid sending (potentially sensitive) data over untrusted network in plaintext.: Do not use insecure URLs

Related
See tslint no-http issue where localhost was resolved to be allowed.

Expected behavior
http://localhost should be allowed.

[A-Katopodis]

Issue was resolved with PRs:
#11
#12