No borders, city militia, and restricted infrastructure

[XHawk87]

An idea to address wild border changes while avoiding making rapid invasions too easy:

• Borders are disabled
• Create new militia units
  • Can't move
  • Unhomed
  • No upkeep
  • Can't be built
  • Can't be bribed
  • No shields for disbanding
• At TC, the most advanced available militia unit appears in each worked tile, and the city centre, and disappear from non-worked tiles
• Create restricted variants of each infrastructure type (road, rail, maglev)
  • Work the same as normal but have no move bonus
  • When militia are defeated, they perform asymmetric warfare in the tile for the rest of the turn
    • Normal infrastructure are replaced with restricted variants
    • At TC, they return to normal

[lmoureaux]

Make sure you consider upkeep, disbanding (free shields by disbanding the ones at city centers?), bribing...

[XHawk87]

Unhomed means no upkeep, right?

[lmoureaux]

For now longturn/freeciv21#2300