Add configuration option to bypass proxy settings for some domains

[jvillafanez]

Description

The proxy config option allows the admin to set a proxy that will be used for the ownCloud requests. The new proxy_ignore option will allow the bypass of that proxy for specific domains

Related Issue

https://github.com/owncloud/enterprise/issues/4979

Motivation and Context

Some domains might not need to go through the proxy.

How Has This Been Tested?

Manually tested

1. Configure mitmproxy and expose a port for it
2. Set the proxy setting in ownCloud to use the proxy configured in step 1
3. Go to the market app and try to load the contents

With the proxy active, the proxy should log the request. It might also reject the request due to SSL certificates, but an error should appear in the proxy.
Setting the new 'proxy_ignore' => ['.owncloud.com'] (for example), the market app is expected to load successfully without going through the proxy, so there shouldn't be any activity there.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Database schema changes (next release will require increase of minor version instead of patch)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests only (no source changes)

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation ticket raised:
• Changelog item, see TEMPLATE

[mmattel]

Hooking myself in, needs a config-to-docs run when merged.

[mmattel]

@jvillafanez you have status 3-to review, this will hang forever if there is no reviewer set...

[phil-davis]

This will need a changelog.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

100.0% Coverage
0.0% Duplication