Created network configuration page

[DGabri]

Please sign (check) the below before submitting the Pull Request:

• I have signed the ntop Contributor License Agreement at https://github.com/ntop/legal/blob/main/individual-contributor-licence-agreement.md
• I have read the contributing guide lines https://github.com/ntop/ntopng/blob/dev/CONTRIBUTING.md
• I have updated the documentation (in doc/src/) to reflect the changes made (if applicable)

Link to the related issue:

Describe changes:

• Created network configuration page. (IP:3000/lua/admin/network_configuration.lua)
• Add the new entry for this page in the menu: scripts/lua/modules/page_utils.lua
• Remove the input box in the current behavioural checks (This was not done as it would break the current ntopng until this REST is completed)
• GET and POST RESTs are at: /lua/rest/v2/set/network/config.lua /lua/rest/v2/get/network/config.lua

[lucaderi]

is_enabled is not necessary

[lucaderi]

Not necessary