[#805] project folders wip
[#805] indentation fix
[#805]

* Made survey groups hierarchical. A survey group can now have a 'parent' survey group
* Added a 'projectMigrations' endpoint to the testHarness which splits surveys in non monitoring survey groups into their own survey group. Non monitoring survey groups can contain at most one survey.
[#805] wip
[#797] Set locale identifier and display name when retrieving survey instance

Based on changes recommended by @mtwestra
[#797] Source code formatting and delete unused code
[#805] more wip
[#797] Always check for `surveyedLocaleIdentifier` and `surveyedLocaleDisplayName`
[#797] Set empty string for missing values
Merge pull request #825 from akvo/issue/797-missing-display-name

[#797] Display name and locale identifiers missing in RAW DATA report
[#435] Ignore empty `questionId`
Merge pull request #826 from akvo/issue/435_copy_question_group

[#435] Ignore empty `questionId` when copying questions
[#797] Set locale identifier and display name when retrieving survey instance

Based on changes recommended by @mtwestra

(cherry picked from commit 80e3176a3e3058bb618f6c4e83fc70a8ea68f71e)
[#797] Always check for `surveyedLocaleIdentifier` and `surveyedLocaleDisplayName`

(cherry picked from commit 608cb273826b6ba8038c40fbeecf63965a657c51)
[#797] Set empty string for missing values

(cherry picked from commit 86d7253546ae2c6364575c943c8194cf4ff8e83b)
[#435] Ignore empty `questionId`

(cherry picked from commit bc4616260dd2878e0d473c23a55b5dcb4b25ecbc)
[#827] Release Notes 1.7.4.1
Merge branch 'release/1.7.4.1'
Merge branch 'master' into develop
[#829] add scale indicator to map