Wine 11 update and various guide and documentation improvements

[helenclx]

This PR aims to improve the repository's install guides and documentation by:

• Updating the Wine 10.17+ with information about Wine 11. Specifically, the steps of downloading and setting up wintypes can be skipped if the user has Wine at version 11 or newer.
• Remove inaccurate information from the AffinityOnLinux install script guide. Only either MSIX or EXE installer is required, not both; there is no way to download only a specific directory from a GitHub repository.
• Adding a section for unofficial methods to install Affinity software on Linux to the main README, with recommendations for users to ask for support from the respective authors directly rather than this AffinityOnLinux repo and Discord. This is done to keep the unofficial methods seprate from the official ones to reduce confusion for users.
• For install methods other than Wine 10.17+, instructing users to select a specific option from Affinity's download page to download the installer in EXE format.
• On the main README, move the bullet list of known issues to the correct position, which is below the "Known Issues" link instead of the "FAQ" link.