Rewrite configuration options

The way configuration was handled was becoming a mess. I've
rewritten it to expose the configuration struct from the
codegen package directly.

This is a very breaking change, so the `--old-config-style` flag will
use the old configuration parsing, and `--output-config` will output
the new style config file from old config to aid in rewriting.

Revert "improve gin support (oapi-codegen#530)"

This reverts commit 11622c2.

It caused a breaking change to existing users.

Update more dependencies

Resolving conflicts previously override the moq library, pull
the latest version and run go mod tidy.

Use go:embed to embed template files

upgrade getkin/kin-openapi to v0.80.0 to fix panic when server is mis…

…sing a path (oapi-codegen#474)

Co-authored-by: Marcin Romaszewicz <47459980+deepmap-marcinr@users.noreply.github.com>

Regenerate example code

This fixes a merge issue from a PR which didn't include some new changes.

fix: parameters starting with number (oapi-codegen#402)

Revert "Fix escaped url parsing (oapi-codegen#381)"

This reverts commit c60f8ae.

I've had to revert this because it breaks an existing test, because
it changes behavior. I will revisit this issue in the future.

Update docs for x-oapi-codegen-extra-tags

Expose openapi3.Schema in the Schema object (oapi-codegen#365)