Pull request: all: reformat yaml, add yaml formatting standard

Merge in DNS/adguard-home from 2297-yaml to master

Closes #2297.

Squashed commit of the following:

commit 85df3a38a14adb1965944ddf14b197c12a213057
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Nov 20 17:52:22 2020 +0300

    all: improve HACKING.md

commit 079acdfe41cc12ab6aa13d7c28dcbf7b7b3c8380
Merge: 202ea078e 3045da174
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Nov 20 17:50:34 2020 +0300

    Merge branch 'master' into 2297-yaml

commit 202ea078e29d88871a32ac6e668dfae6db802bab
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Nov 12 20:25:42 2020 +0300

    all: reformat yaml, add yaml formatting standard

.golangci.yml

@@ -1,78 +1,77 @@
 # options for analysis running
-run:
+'run':
   # default concurrency is a available CPU number
-  concurrency: 4
+  'concurrency': 4
 
   # timeout for analysis, e.g. 30s, 5m, default is 1m
-  deadline: 2m
+  'deadline': '2m'
 
   # which files to skip: they will be analyzed, but issues from them
   # won't be reported. Default value is empty list, but there is
   # no need to include all autogenerated files, we confidently recognize
   # autogenerated files. If it's not please let us know.
-  skip-files:
-    - ".*generated.*"
-    - dnsfilter/rule_to_regexp.go
-    - util/pprof.go
-    - ".*_test.go"
-    - client/.*
-    - build/.*
-    - dist/.*
-
+  'skip-files':
+  - '.*generated.*'
+  - 'dnsfilter/rule_to_regexp.go'
+  - 'util/pprof.go'
+  - '.*_test.go'
+  - 'client/.*'
+  - 'build/.*'
+  - 'dist/.*'
 
 # all available settings of specific linters
-linters-settings:
-  errcheck:
+'linters-settings':
+  'errcheck':
     # [deprecated] comma-separated list of pairs of the form pkg:regex
     # the regex is used to ignore names within pkg. (default "fmt:.*").
     # see https://github.com/kisielk/errcheck#the-deprecated-method for details
-    ignore: fmt:.*,net:SetReadDeadline,net/http:^Write
-  gocyclo:
-    min-complexity: 20
-  lll:
-    line-length: 200
+    'ignore': 'fmt:.*,net:SetReadDeadline,net/http:^Write'
+  'gocyclo':
+    'min-complexity': 20
+  'lll':
+    'line-length': 200
 
-linters:
-  enable:
-    - deadcode
-    - errcheck
-    - govet
-    - ineffassign
-    - staticcheck
-    - unused
-    - varcheck
-    - bodyclose
-    - depguard
-    - dupl
-    - gocyclo
-    - goimports
-    - golint
-    - gosec
-    - misspell
-    - stylecheck
-    - unconvert
-  disable-all: true
-  fast: true
+'linters':
+  'enable':
+  - 'bodyclose'
+  - 'deadcode'
+  - 'depguard'
+  - 'dupl'
+  - 'errcheck'
+  - 'gocyclo'
+  - 'goimports'
+  - 'golint'
+  - 'gosec'
+  - 'govet'
+  - 'ineffassign'
+  - 'misspell'
+  - 'staticcheck'
+  - 'stylecheck'
+  - 'unconvert'
+  - 'unused'
+  - 'varcheck'
+  'disable-all': true
+  'fast': true
 
-issues:
+'issues':
   # List of regexps of issue texts to exclude, empty list by default.
   # But independently from this option we use default exclude patterns,
   # it can be disabled by `exclude-use-default: false`. To list all
   # excluded by default patterns execute `golangci-lint run --help`
-  exclude:
-    # structcheck cannot detect usages while they're there
-    - .parentalServer. is unused
-    - .safeBrowsingServer. is unused
-    # errcheck
-    - Error return value of .s.closeConn. is not checked
-    - Error return value of ..*.Shutdown.
-    # goconst
-    - string .forcesafesearch.google.com. has 3 occurrences
-    # gosec: Profiling endpoint is automatically exposed on /debug/pprof
-    - G108
-    # gosec: Subprocess launched with function call as argument or cmd arguments
-    - G204
-    # gosec: Potential DoS vulnerability via decompression bomb
-    - G110
-    # gosec: Expect WriteFile permissions to be 0600 or less
-    - G306
+  'exclude':
+  # structcheck cannot detect usages while they're there
+  - '.parentalServer. is unused'
+  - '.safeBrowsingServer. is unused'
+  # errcheck
+  - 'Error return value of .s.closeConn. is not checked'
+  - 'Error return value of ..*.Shutdown.'
+  # goconst
+  - 'string .forcesafesearch.google.com. has 3 occurrences'
+  # gosec: Profiling endpoint is automatically exposed on /debug/pprof
+  - 'G108'
+  # gosec: Subprocess launched with function call as argument or cmd arguments
+  - 'G204'
+  # gosec: Potential DoS vulnerability via decompression bomb
+  - 'G110'
+  # gosec: Expect WriteFile permissions to be 0600 or less
+  - 'G306'