Improve following Github discussions

* Add stack.yaml to install/ folder
* Add Stack and Cabal templates for hie.yaml for install/ folder
* Add and cleanup documentation about hie.yaml
* Add comment about building for Stack

Author: sir4ur0n

Diff for: README.md

@@ -497,15 +497,27 @@ args = ["--lsp"]
 
 ### Hacking on haskell-language-server
 
-Haskell-language-server can be used on its own project.  We have supplied
-preset samples of `hie.yaml` files for stack and cabal, simply copy
-the appropriate template to `hie.yaml` and it should work.
+Haskell-language-server can be used on itself. We provide
+preset samples of `hie.yaml` for Cabal and Stack.
 
-- `hie.yaml.cbl` for cabal
-- `hie.yaml.stack` for stack
+Note: the `./install/` folder is not directly tied to the project so it has dedicated `./install/hie.yaml.[cbl|stack]` 
+templates.
 
-Two sample `hie.yaml` files are provided, `hie.yaml.stack` for stack
-usage, `hie.yaml.cbl` for cabal. Simply copy the relevant one to be
-`hie.yaml` and it should work.
+#### Using Cabal
 
-The developers tend to hang out at [our IRC channel](https://webchat.freenode.net/?channels=haskell-ide-engine) at `#haskell-ide-engine` on `freenode`.
+```shell
+$ cp hie.yaml.cbl hie.yaml
+$ cp install/hie.yaml.cbl install/hie.yaml
+```
+
+#### Using Stack
+
+Note: Stack project must also be built once until [this issue](https://github.com/commercialhaskell/stack/issues/5213) is fixed.
+
+```shell
+$ cp hie.yaml.stack hie.yaml
+$ cp install/hie.yaml.stack install/hie.yaml
+$ stack build --test --no-run-tests
+$ cd install
+$ stack build
+```

Diff for: hie.yaml.cbl

@@ -6,9 +6,6 @@ cradle:
     - path: "./test/testdata/"
       config: { cradle: { none:  } }
 
-    - path: "./install/"
-      config: { cradle: { none:  } }
-
     - path: "./"
       config:
         cradle:

Diff for: hie.yaml.stack

@@ -6,9 +6,6 @@ cradle:
     - path: "./test/testdata/"
       config: { cradle: { none:  } }
 
-    - path: "./install/"
-      config: { cradle: { none:  } }
-
     - path: "./"
       config:
         cradle:

Diff for: install/hie.yaml.cbl

@@ -0,0 +1,3 @@
+cradle: 
+  cabal: 
+    component: "lib:hls-install"

Diff for: install/hie.yaml.stack

@@ -0,0 +1,3 @@
+cradle: 
+  stack: 
+    component: "hls-install:lib"

Diff for: install/stack.yaml

@@ -0,0 +1,13 @@
+resolver: lts-14.27 # Last 8.6.5 
+
+packages:
+  - .
+
+extra-deps:
+  - cabal-install-parsers-0.3.0.1
+  - Cabal-3.2.0.0
+  - binary-instances-1.0.0.1
+  - lukko-0.1.1.2
+
+nix:
+  packages: [ icu libcxx zlib ]