feat!: drop modules, general refactor and cleanup

runtime/queries/beancount/folds.scm

@@ -0,0 +1,4 @@
+[
+    (transaction)
+    (section)
+] @fold

runtime/queries/beancount/highlights.scm

@@ -0,0 +1,24 @@
+(date) @field
+(txn) @attribute
+(account) @type
+(amount) @number
+(incomplete_amount) @number
+(compound_amount) @number
+(amount_tolerance) @number
+(currency) @property
+(key) @label
+(string) @string
+(narration) @string @spell
+(payee) @string @spell
+(tag) @constant
+(link) @constant
+[
+ (minus) (plus) (slash) (asterisk)
+] @operator
+(comment) @comment @spell
+[
+    (balance) (open) (close) (commodity) (pad)
+    (event) (price) (note) (document) (query)
+    (custom) (pushtag) (poptag) (pushmeta)
+    (popmeta) (option) (include) (plugin)
+] @keyword