fix problems with some urls when use --public_url

[emiliopardo]

Hello

I've had some problems when trying to use tileserver-gl through a proxy.

These problems are related to the static files located in the path "/usr/src/app/public/"

The "wmts.tmpl" file does not contemplate the use of {{public_url}}, it always uses {{base_url}}

In the index.tmpl file in the wmts section, {{public_url}} is not considered in the link to the capabilities of the service.

In the index.css file all calls to styles that have url fail because they cannot be parameterized with {{public_url}}

If these styles are removed and included within index.tmpl in the header with <style> you can use {{public_url}}

These changes are minor and make it easier to use tileserver-gl through a proxy.

Thanks

[acalcutt]

I Merged #605 , which sets BaseUrl to PublicUrl if the option is set. I think this should make the changes in wmts.tmpl not needed anymore.

I also merge #501 , which fixes the public url in index

I think the only part left to this change would be the css, which I'm not sure about.

[mnutt]

I believe the font-face definitions can be left in the css file, and use relative paths to the font files.

[tonofll]

UP this PR
Although API endpoints perfectly work by using --public_url parameter, certain UI elements and links are completely broken when you place tileserver-gl behind a proxy.

[mloskot]

I believe this has been fixed long ago

• Fix URL to WMTS capabilities to be based on public URL #501

[mloskot]

@tonofll @acalcutt

UP this PR Although API endpoints perfectly work by using --public_url parameter, certain UI elements and links are completely broken when you place tileserver-gl behind a proxy.

This is weird indeed, because the public_url seems to be used across the UI template, e.g.

tileserver-gl/public/templates/index.tmpl

Lines 64 to 72 in 9bb270b

	{{#if serving_data}}
	<a href="{{public_url}}styles/{{@key}}/style.json{{&../key_query}}">GL Style</a>
	{{/if}}
	{{#if serving_rendered}}
	{{#if serving_data}}| {{/if}}<a href="{{public_url}}styles/512/{{@key}}.json{{&../key_query}}">TileJSON</a>
	{{/if}}
	{{#if serving_rendered}}
	| <a href="{{public_url}}styles/{{@key}}/wmts.xml{{&../key_query}}">WMTS</a>
	{{/if}}

There is a peculiar issue though:

• I'm using NGINX proxy
• I run pass --public_url https://svc.example.com/test/tiles (or --public_url https://svc.example.com/test/tiles/, no difference)
• I access https://svc.example.com/test/tiles and URL-s on the default frontpage are generated without the part /tiles/ like https://svc.example.com/test/styles/basic-preview/style.json instead of
  https://svc.example.com/test/tiles/styles/basic-preview/style.json
• I access https://svc.example.com/test/tiles/ with trailing / and all URL-s on the default frontpage are correctly generated

The only issue I noticed is the missing thumbnails:

but that seems to be due to the URL-s missing #, I think, like here
https://svc.example.com/test/tiles/styles/basic-preview/11/1072/717.png
instead of
https://svc.example.com/test/tiles/styles/basic-preview/#11/1072/717.png