**What**
- Add Dockerfile testp to mov ethe vendor folder up from the function
  volder to function root. This allows the user to control the vendor
  folder and avoid collisions/validation errors from Go in modules mode
- This new flow allows dynamic downloading of Go modules _or_ disabling
  Go modules and only using vendor. You can not use vendor _and_ modules
  at the same time due to how Go will validate that the vendor folder
  and the go.mod are insync

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

**What**
- Remove the tidy step because it is not needed and does not work as
  expected

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

**What**
- Remove check for modules = off from the middleware template. This
  isn't needed

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

**What**
- Add scripting that handles copying the function's go.mod to the
  function root. This requires several mutations to handle renaming the
  module and dealig with local replacements of the function
- Add scriptin to handle the vendor/modules.txt. It also handles
  mutations to deal with the local replacement of the function code

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

**What**
- Extract the vendor and modules cleanup into a separate shell script.
  This provides more space for documenting each step cleanly.
- This scripting also removes the need for the `GO_REPLACE.txt` hack,
  it will automatically modify any local replacements in the original
  go.mod file, so that they work as expected.
- Update the README to describe how dependencies work in the three
  supported modes: modules with vendoring, modules without vendoring,
  and traditional vendoring via dep.

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

**What**
- Add check and skip when the funciton folder is not a module
Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>