This caused the lockfiles to ignore certain dependencies

Removes previous hack that needed to read current nimble file state

This changes the lock file structure, but compaitability shouldn't be affected

Using nimlangserver since that was that project I first noticed it with

Will now investigate other tests

Force yes in tests

Fix tests

Go back to non destructive uninstall for deps

Error says it is due to stdlib but it works a few lines later

- Fixes nim-lang#953

Allow having nim as locked dependency.

- I will add unit tests once we agree on the approach and once nimble related
changes in nim are merged (I will link the PR in comment). Ditto for the
documentation. In order that change to work we have to add nim package in nimble
packages repo and also add alias compiler -> nim to avoid breaking backward
compatibility.

Here it is the flow:

``` bash
nimble develop nim
nimble lock
```

After that `nimble install` and `nimble build` commands will use the locked
`nim` version