BACKLOG-1581 -- Document interfaces mentioned in MT doc

What was done:
1) added \ changed comments based on DOC team feedback
[BACKLOG-872] Restructure Data Access to allow for deterministic build
Merge pull request #2164 from mdamour1976/cleanup

[BACKLOG-872] Restructure Data Access to allow for deterministic build
Merge pull request #2160 from kolinus/BACKLOG-1581

BACKLOG-1581 -- Document interfaces mentioned in MT doc
[BACKLOG-872] Fixes due to the introduction of the Property type in
metadata.
Merge pull request #2168 from e-cuellar/master

[BACKLOG-872] Fixes due to the introduction of the Property type in metadata.
[BISERVER-12093] - Cannot delete invalid Data Source - the check for mondrian schema file was deleted because we can't suppose that it is a valid xml file. Also was changed processing mondrian catalogs in method "loadCatalogsIntoCache".
BACKLOG-1178: Document File Management for the DI Server

There are jMeter tests for DI server: Document File Management, User Roles etc.
Merge pull request #2163 from MikhailGorbachev/BISERVER-12093

[BISERVER-12093] - Cannot delete invalid Data Source
Merge pull request #2161 from TatsianaKasiankova/BACKLOG-1178

BACKLOG-1178: Document File Management for the DI Server
Revert "[BACKLOG-872] Restructure Data Access to allow for deterministic build"
Revert "[BACKLOG-872] Fixes due to the introduction of the Property type in metadata."
Merge pull request #2170 from pentaho/revert-2168-master

Revert "[BACKLOG-872] Fixes due to the introduction of the Property type...
Merge pull request #2171 from pentaho/revert-2164-cleanup

Revert "[BACKLOG-872] Restructure Data Access to allow for deterministic...
BISERVER-12315 - XSS - Cross Site Scripting vulnerability in Rename Popup
Merge pull request #2162 from Aliaksandr-Kastenka/BISERVER-12315

BISERVER-12315 - XSS - Cross Site Scripting vulnerability in Rename Popu...
[BISERVER-12105] - Import-export.sh utility doesnt work if a folder/file name has spaces in it - fixed transferring parameters in shell script
[BACKLOG-1183]: Document Plug-in Management for the DI Server

There are jmeter tests.
Merge pull request #2173 from TatsianaKasiankova/BACKLOG-1183

[BACKLOG-1183]: Document Plug-in Management for the DI Server
Merge pull request #2172 from MikhailGorbachev/BISERVER-12105

[BISERVER-12105] - Import-export.sh utility doesnt work if a folder/file name has spaces in it