Rp2

* added generic country plugin (for use in countries that don't have country-specific support yet)
* various improvements to documentation

* optimized FIFO accounting from quadratic to linear (115)
* optimized LIFO and HIFO accounting from quadratic to m*log(n) (116)
* added support for Ireland (122)
* added negative staking (119)
* fixed negative balance bug (113)
* reworked country-specific documentation: added dedicated page with country-specific information (see docs/supported_countries.md)

* re-enabled LIFO and HIFO accounting methods (see discussion at 79)
* added Python 3.11 to test matrix (107)
* on certain Linux distribution the mpdecimal library is missing, which causes runtime errors. This is now detected and reported to the users (108)
* added -n CLI option to allow negative balances on exchanges (106)
* multiple small documentation improvements

* added support for Spain (see 97)

* fixed small bug in rp2_full_report generator: OUT transactions had slightly incorrect fiat_out field. The displayed value was fiat_out_no_fee - fiat fee, instead of fiat_out_no_fee. This bug didn't affect actual tax computation or the tax_report output: it only affected the fiat_out field in the OUT table of rp2_full_report.

* added new RP2RuntimeError to handle non-recoverable problems without using Exception