Improve RTL support by using CSS Logical Properties

[babakfp]

fixes: #1191

only the files in pagefind_ui folder are edited.

not sure about pagefind_ui/default/_dev_files/water.css

not sure about logical properties with things like env(safe-area-inset-left):

padding-inline-start: max(16px, env(safe-area-inset-left));

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not sure what is :is(*, #\#), but based on the merged changes in https://github.com/Pagefind/pagefind/pull/1086/changes#diff-46dab2ee5ab4f506b722261382bdc989883b68f44f5930b7890bc052adc8aa7bL719, changes to :is(*, #\#) should be fine

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i couldn't run the project and test the changes!

after a whole bunch of fighting with wsl, docker and whatever, i reached this point and, honestly, this shit sucks... why does even a search util needs rust and docker?! :|

|> just install                                                                                                                                                            
Error: Node.js is required but not installed. Please install Node.js first.                                                                                                
error: recipe `install-npm` failed on line 17 with exit code 1