feat(documentstore): should throw relevant exception rather than digest the exception

[pujavs]

Describe the bug
A clear and concise description of what the bug is.

• Parent issue: 2419
• Discussion chat [thread] (https://chat.gluu.org/group/service_config_api?msg=rYXXDq4ihP92W67Ng)

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[yurem]

According to @pujavs "...Right now methods return boolean making it difficult to calling client to understand the issue."

[yurem]

@shekhar16 LocalDocumentStore and DBDocumentStore should throw WriteDocumentException and DocumentException with parent exception. Both exceptions should extends RuntimeException. We don't need to add them to DocumentStore methods declarions

[shekhar16]

code has been merged closing this ticket. Please let me know if anything needed.