feat: Implement config update API

[shadinaif]

Description:

Replace the mock API to a real one PUT /api/fx/config/v1/draft

Steps to apply the update:

• Verify that the user can edit the key
• If reset option is on; then delete the key from the draft
• If reset option is off; then update the field with multi-user edit check:
  • create a function receives current_value, new_value, and key_path
  • the function update the value of the key specified in key_path if:

{{key_path}} does not exist AND config_draft.{{key_path}} does not exist
OR
config_draft.{{key_path}} exists AND current_value matches the current value of config_draft.{{key_path}}
OR
config_draft.{{key_path}} does not exist AND {{key_path}} exists AND current_value matches the current value of {{key_path}}

Important:

• Apply the update using ORM update and filter with no value comparison in the Python level. Because using fetch and compare will defeat the purpose of the (multi-user edit check) mechanism

Related PRs:

• to be filled by the SE