webproxy: T563: migrate from old Perl code to XML and get_config_dict()

[c-po]

Change Summary

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

https://phabricator.vyos.net/T563
https://docs.vyos.io/en/latest/configuration/service/webproxy.html

Component(s) name

webproxy

Proposed changes

• Drop old Vyatta Perl implementation and go forward using XML and get_config_dict()

How to test

Integrated Smoketests or

set service webproxy listen-address 172.18.254.201 disable-transparent
set service webproxy authentication method ldap
set service webproxy authentication ldap base-dn "DC=vyos,DC=net"
set service webproxy authentication ldap username-attribute cn
set service webproxy authentication ldap bind-dn CN=proxyuser,CN=Users,DC=vyos,DC=net
set service webproxy authentication ldap filter-expression (cn=%s)
set service webproxy authentication ldap server ldap.vyos.net
set service webproxy authentication ldap use-ssl

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[dmbaturin]

Great! One less legacy package!