[#74] docs: Describe converters

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

docs/policy_converters.md

@@ -93,7 +93,6 @@ and consists of the following fields:
 | `Key`    | Property key                                                                              |                                                                   
 | `Value`  | Property value                                                                            |                                                                   
 
-
 Conditions operators:
 
 | AWS conditions operator     | FrostFS condition operator  | Comment                                                           |
@@ -191,16 +190,16 @@ transforms to FrostFS conditions:
 
 #### Actions
 
-Each action allows some s3-gw methods, so we must transform action to specific method names 
-(you can see exact mapping in table in [this file](../iam/converter_s3.go)). 
+Each action allows some s3-gw methods, so we must transform action to specific method names
+(you can see exact mapping in table in [this file](../iam/converter_s3.go)).
 
 For example the following actions:
 
 ```json
 {
   "Action": [
-    "s3:DeleteObject", 
-    "iam:CreateUser" 
+    "s3:DeleteObject",
+    "iam:CreateUser"
   ]
 }
 ```
@@ -220,9 +219,9 @@ transforms to
 }
 ```
 
-As we can see any `iam:*` action transformed as it is. But `s3:*` actions transforms according to 
-[spec rules](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazons3.html) 
-and s3-gw [method names](https://git.frostfs.info/TrueCloudLab/frostfs-s3-gw/src/commit/2ab655b909c40db6f7a4e41e07d8b99167f791bd/api/middleware/constants.go#L3-L76).
+As we can see any `iam:*` action transformed as it is. But `s3:*` actions transforms according to
+[spec rules](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazons3.html) and s3-gw
+[method names](https://git.frostfs.info/TrueCloudLab/frostfs-s3-gw/src/commit/2ab655b909c40db6f7a4e41e07d8b99167f791bd/api/middleware/constants.go#L3-L76).
 
 #### Resources
 
@@ -249,10 +248,9 @@ Resource is transformed as it is:
 
 #### Principals
 
-To check user s3-gw uses special condition request property (`Owner`), so when AWS policy contains principal field 
-it transforms to rule with appropriate condition. To get correct `Owner` property value 
-special user resolver (`S3Resolver` interface in [converter_s3 file](../iam/converter_s3.go)) must be provided into 
-convert function.
+To check user s3-gw uses special condition request property (`Owner`), so when AWS policy contains principal field
+it transforms to rule with appropriate condition. To get correct `Owner` property value special user resolver
+(`S3Resolver` interface in [converter_s3 file](../iam/converter_s3.go)) must be provided into convert function.
 
 For example such AWS json statement:
 
@@ -261,7 +259,7 @@ For example such AWS json statement:
   "Effect": "Allow",
   "Action": "*",
   "Resource": "*",
-  "Principal":{
+  "Principal": {
     "AWS": "arn:aws:iam::111122223333:user/JohnDoe"
   }
 }
@@ -308,8 +306,8 @@ For example the following actions:
 ```json
 {
   "Action": [
-    "s3:DeleteObject", 
-    "iam:CreateUser" 
+    "s3:DeleteObject",
+    "iam:CreateUser"
   ]
 }
 ```
@@ -347,7 +345,7 @@ To transform resources the following is being performed:
 
 * Bucket name is resoled to container id (by providing `NativeResolver` interface implementation to converter)
 * Object name is transformed to condition with special `FilePath` attribute
-(that present on every object that was uploaded via s3-gw)
+  (that present on every object that was uploaded via s3-gw)
 
 For example, the following AWS policy statement:
 
@@ -392,10 +390,10 @@ transforms to FrostFS native policy rule:
 
 #### Principals
 
-To check user s3-gw uses special condition request property (`$Actor:publicKey`), so when AWS policy contains principal field
-it transforms to rule with appropriate condition. To get correct `$Actor:publicKey` property value
-special user resolver (`NativeResolver` interface in [converter_native file](../iam/converter_native.go)) must be provided into
-convert function.
+To check user s3-gw uses special condition request property (`$Actor:publicKey`), so when AWS policy contains principal
+field it transforms to rule with appropriate condition. To get correct `$Actor:publicKey` property value
+special user resolver (`NativeResolver` interface in [converter_native file](../iam/converter_native.go)) must be
+provided into convert function.
 
 For example such AWS json statement: