* refactor all code that builds csources
* fixup
* nim_csourcesDir_v0 + nim_csourcesDir
* remove deprecated, unused scripts from ci/
* reuse nimCsourcesHash in ci
* simplify CI pipelines by reusing nimBuildCsourcesIfNeeded
* simplify ci_docs.yml by reusing nimBuildCsourcesIfNeeded
* cleanup
* use csources_v1 as destination dir
* fixup
* remove pushCsources
* address comment: remove build.sh support for now
* fixup
* CIs: attempt to use csources_v1
* also updated the BSDs
* also updated azure pipelines
* std modules should not itself use the 'std/' import dir...
* compiler has to be careful with std/ for v1 booting
* update doc CI filter to include the files mostly likely to require doc rebuild
* remove code duplication in ./config/nimdoc.cfg; show link to compiler docs, various fixes
* walkDirRecFilter, factor nativeToUnixPath workaround
* glob for getRst2html
* docslocal: 40s to build all docs
* revert code dedup in github actions which did not work alas...
* fixups
