apache: rewriting the missing trailing slash when in an iframe breaks the page

[apolopena]

Describe the bug

When using SimpleBrowser or any iframe and using a gitpod/project url (ending in a directory name) without a trailing slash, the rewrite is triggered to rewrite the url with a trailing slash but $scheme is used so the rewrite uses http when the parent of the iframe is https. This triggers a mixed content error and the page does not load.

This issue of course does not occur when using an external browser

Screenshots

Steps to reproduce

with a default starter run the url in the simple browser with /phpmayadmin rather than /phpmyadmin/
inspect the page

You will see the mixed content errors and a white screen.

Expected behavior

trailing slash rewrites should not break the page when displayed in an iframe.

Additional information

To fix this we will use brute force by rewriting trailing slashes to use https instead of $scheme.
Since gitpod uses https this hardcoded fix will not break anything.

[apolopena]

workaround this for now by always appending urls ending in a directory with a trailing slash.
You can also do this with op by doing something like this: op phpmyadmin/

[apolopena]

fixed by overwriting default apache2.conf to replace:
ServerName ${APACHE_SERVER_NAME}
with
ServerName https://localhost
This seems to force redirected trailing slash requests to use https rather than http

[apolopena]

depends on #135