lighttpd: lighttpd.conf modernize

[gstrauss]

Description

lighttpd: lighttpd.conf modernize

• collect debug logging directives; remove duplication
• update to use modern lighttpd.conf syntax
• use lighttpd default built-in web mime types

Motivation and Context

Improve lighttpd.conf along with phoenix-rtos/phoenix-rtos-ports#90

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: (list targets here).

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
  => Depends on lighttpd: lighttpd 1.4.79 phoenix-rtos-ports#90 to update lighttpd version.
• I will merge this PR by myself when appropriate.

[gstrauss]

@agkaminski, @Darchiv similar to my post in #1262 (comment), please review if the team has the resources and time available to participate on the PRs assigned to them. Thank you.