improve docs

docs/general.md

@@ -1,30 +1,7 @@
 # Required variables
-These variables are required by some roles. Example values included.
+These variables might be required by multiple roles and need to be defined. Example values below.
 
 ```
 email: 'admin@domain.tld'
 ```
 
-# Default variables
-These variables have default values (shown below) which can be overridden.
-
-```
-install_packages:
-  - vim
-  - git
-  - etckeeper
-  - net-tools
-  - nmap
-  - ncdu
-  - fish
-  - parted
-```
-
-# Optional variables
-These variables are not required and not defined by default. Example values included.
-
-```
-delete_packages:
-  - nano
-  - curl
-```