feat: at_client put method - introduce shouldEncrypt flag

[murali-shris]

Fixes #1401
Depends on atsign-foundation/at_server#2099 for intermittent functional test failure in sync_multiple_client_test

- What I did

• Ability for clients to set shouldEncrypt=false when they don't want to encrypt data for self and shared key

- How I did it

• added a flag shouldEncrypt with default value=true in PutRequestOptions. This value will be ignored for public keys(metadata.isEncrypted is always false). For self and sharedkey this value will be honoured and data will be encrypted(shouldEncrypt=true) or not encrypted(shouldEncrypt=false)
• Refactored put_request_transformer for readability
• Changes in get_response_transformer to handle two scenarios 1) isEncrypted for new data(post these changes where isEncrypted=true for self/shared keys) 2) isEncrypted=false for old self/shared key.
• modified sync_multiple_client_test to replicate the intermittent issue consistently
• added unit and functional test

- How to verify it

• tests should pass
  Dependency tests
  test: check onboarding cli for at_client publish at_libraries#673
  test: noports test for at_client and onboarding cli publish noports#1387
  TODO:
  Replace dependency overrides with published versions
  at_commons PR to be reviewed and merged
  feat: at_commons changes for setting isEncrypted for both true and false at_libraries#669

[murali-shris]

fix for functional test issue in server
https://github.com/atsign-foundation/at_server/pull/2099/files

[gkc]

What does "by default" mean? Is it more accurate to say that "isEncrypted will be set to true when data is encrypted"?

[murali-shris]

isEncrypted will be set to true for self/shared keys, if caller doesn't set anything in PutRequestionOptions. I will change the wording.

[gkc]

#1398 (comment)