feat(provider): add VPNsecure.me

[qdm12]

Remaining tasks

• [x] Update servers.json
• [x] Update digests for servers.json
• [x] Read private key file (?)
• [x] Adapt Openvpn configuration with their configs
• [ ] Test image
• [x] Fix Poltavs\u0026#039;ka Oblast\u0026#039;
• [ ] Change vpn secure to be vpnsecure

Fixes #685