Figure.coast: Plot continents, countries, shorelines, rivers, and borders

*This issue serves as the central place for discussing and tracking the implementation of the `coast` method in PyGMT. The issue will be closed when the initial implementation is complete. Progress is tracked at https://github.com/orgs/GenericMappingTools/projects/3.*

## Documentation

- GMT: https://docs.generic-mapping-tools.org/dev/coast.html
- GMT.jl: https://www.generic-mapping-tools.org/GMTjl_doc/documentation/modules/coast
- PyGMT: https://www.pygmt.org/dev/api/generated/pygmt.Figure.coast.html

## GMT Option Flags and Modifieres

☑️: *Implemented*; ⬜: *To be implemented/discussed*; ~~Strikethrough~~: *Won't implement*.

* [x] `-R`: `region`
* [x] `-J`: `projection`
* [ ] `-A`
* [x] `-B`: `frame`
* [x] `-C`: `lakes`/`river_lakes` #4376
* [x] `-D`: `resolution` #4013
* [ ] `-E`
* [ ] `-G`: `land`
* [x] `-G`: #4241
* [ ] `-G` for clipping: #3878
* [x] `-F`: `box`. No longer needed after #4015, #4164, #4051
* [x] `-I`: `rivers` #4242
* [x] `-L`: Add a map scale. Will be implemented in #4015
* [ ] `-M`
* [x] `-N`: `borders` #4257
* [ ] `-Q`
* [ ] `-S`: `water`
* [x] `-S` #4241
* [ ] `-S` for clipping: #3878
* [x] `-Td`: Add a directional rose. Will be implemented in #4164
* [x] `-Tm`: Add a magnetic rose. Will be implemented in #4051
* [x] `-W`: `shorelines` #4258
* [ ] ~~`-U`~~: Use `Figure.timestamp` instead.
* [x] `-V`: verbose
* [ ] ~~`-X`/`-Y`~~: Use `Figure.shift_origin` instead.
* [ ] `-bo`
* [x] `-c`: panel
* [ ] `-do`
* [x] `-p`: `perspective`
* [x] `-t`: `transparency`
* [ ] `-:`
* [ ] ~~`--PAR=value`~~: Use `pygmt.config` instead.

## Linked Pull Requests

- [X] Initial feature implementation
- [x] Add a tutorial or gallery example

## Related Issues and Discussions

*Add links to related wrapper discussions, API design threads, or upstream GMT changes here.