Gitpod context URL doesn't support file paths with spaces or backslashes

[Jan Keromnes]

Describe the bug
When trying to open the GitHub URL of a file with spaces in Gitpod, the file is not opened.

To Reproduce

1. Try to open https://gitpod.io/#https://github.com/jankeromnes/gitpod-test/blob/master/file%20with%20spaces.txt
   • or https://gitpod.io/#https://github.com/jankeromnes/gitpod-test/blob/master/back%5Cslash.txt
2. Wait for workspace to load
3. The requested file file with spaces.txt (or back\slash.txt) does not open automatically
4. The browser console says root ERROR Cannot find segment 'file%20with%20spaces.txt' of given path!
   • or root ERROR Cannot find segment 'back%5Cslash.txt' of given path!

Expected behavior
The file file with spaces.txt (or back\slash.txt) should automatically open.

Double-clicking on the file in the file tree, or running gp open file\ with\ spaces.txt, or gp open "file with spaces.txt" (or gp open back\\slash.txt) all succeed in opening the file.