Replace glide with Go modules

[erthalion]

Work in progress, but I guess it would be nice to have.

[FxKu]

resolves #148

[sdudoladov]

I found the original module proposal helpful to understand the modules' system while reviewing the operator's kubectl plugin (it switched from Glide to modules recently )

[FxKu]

@erthalion could you rebase? Our test pipeline in the master branch is currently failing because the new kubectl-pg plugin needs GO111MODULE=on. Maybe this is a good moment for the operator to switch to Go modules, too.

[FxKu]

A change in the code-generator source code made me change the package/directory name from acid.zalan.do to acidzalando. However, the group name remains the same (with dots).

I created a PR in the codegen repo. If they consider changing it back we could also switch back and not break things.

[sdudoladov]

A change in the code-generator source code made me change the package/directory name from acid.zalan.do to acidzalando.

What impact did similar renaming have on other operators that depend on the code generator ?
if someone uses the renamed API the name change will break their code ?

[sdudoladov]

FYI go 1.13 was released, it changes the way modules are configured

[FxKu]

Looks like they are going to fix it, so we can leave the package name as it was before. Will update the PR, when it's merged on the code-generator side.

[sdudoladov]

👍

[FxKu]

👍

[sdudoladov]

👍