Make request body size limit configurable

[FabijanC]

Usage related changes

• Close Request body size limit should be configurable #408
• Introduce a new CLI parameter: --request-body-size-limit <BYTES>
  • Default: 2000000 (2 MB) - so far this was the only value used
  • This is more flexible than implementing a boolean flag parameter

Development related changes

• Refactor: extract host, port, timeout and request_body_size_limit to ServerConfig
• Remove redundant code from ServerConfig

Checklist:

• Checked the relevant parts of development docs
• Applied formatting - ./scripts/format.sh
• No linter errors - ./scripts/clippy_check.sh
• No unused dependencies - ./scripts/check_unused_deps.sh
• Performed code self-review
• Rebased to the latest commit of the target branch (or merged it into my branch)
• Updated the docs if needed, including the TODO section
• Linked the issues which this PR resolves
• Updated the tests if needed; all passing (execution info)

[mikiw]

looks legit

[marioiordanov]

with the addition of this new cli param request_body_size_limit, I think its time to split the timeout option and this new one into separate config, which are related to configuration on the infrastructure part of the application. The other ones are options for the business logic