Add team portals

[chrahunt]

Team portals are a new TagPro feature that only allow players from the corresponding team to pass through.

They use new textures, one for red and one for blue, with the same dimensions as the original portal texture image.

From the wiki, the relevant tile IDs are:

ID	Tile
24	Active red portal
24.1	Inactive red portal
24.11	Inactive red portal (respawn warning)
25	Active blue portal
25.1	Inactive blue portal
25.11	Inactive blue portal (respawn warning)

These are the places that need to be updated

1. Add the base tile IDs (24, 25) to the recording script, so their dynamic values are recorded
2. Add definitions to mapElements and floor_tiles in tiles.js, probably using the existing neutral portal texture coordinates
3. (blocked on Resolve licensing of default texture pack #265) Add default textures, texture upload UI elements, and wire up custom texture persistence
4. Update the team portal definitions to use the new textures

[chrahunt]

1 and 2 addressed in #271.