Ensure frontend options are applied appropriately to all frontends
Ensure frontend options are applied appropriately to all frontends

- The HTTP frontend now supports accept-proxy.
- Bugs where accept-proxy was not honored during mutual TLS have been
resolved
- `ha_proxy.client_cert` is no longer required to enable TLS. It is
   still honored to enable mutual tls, but the boshrelease will also
   use the presence of the following parameters to enable mutual TLS:

   - `ha_proxy.client_ca_file`
   - `ha_proxy.client_revocation_list`
   - `ha_proxy.crt_list.<i>.client_ca_file`
   - `ha_proxy.crt_list.<i>.client_revocation_list`
   - `ha_proxy.crt_list.<i>.verify` - only when value is not "none"

- The following options are now honored in the `:4443` backend:
  - `ha_proxy.cidr_whitelist`
  - `ha_proxy.cidr_blacklist`
  - `ha_proxy.block_all`
  - `ha_proxy.hsts_*`
  - `ha_proxy.rsp_headers`

- The X-Forwarded-Client_Cert now is set for requests in the `:4443`
  backend.

- The X-Forwarded-Proto header behavior in the `:4443` backend now
  matches the behavior in the `:443` backend

Fixes #95

cloudfoundry-community/cf-haproxy-boshrelease,cloudfoundry-community/cf-haproxy-boshrelease,cloudfoundry-community/cf-haproxy-boshrelease