Merge #16611: build: Remove src/obj directory from repository

b6e9ff8 build: Remove src/obj directory from repository (Wladimir J. van der Laan)

Pull request description:

  This directory is automatically created by the build process (in the build target directory, see #16588) and doesn't need to be in the repository nor in the tarballs.

  Move associated ignore directive to top-level `.gitignore` file.

ACKs for top commit:
  hebasto:
    Concept ACK b6e9ff8

Tree-SHA512: 5f3f5a0e8f19ecf925eb16cab327c3023b8512731bbaad5875828da7a25fdda1b77f6fbd06c002a383913627dc9b552f09ad27c57bcf0cb020ed3b1f506e5fef

.gitignore

@@ -35,6 +35,7 @@ libtool
 src/config/bitcoin-config.h
 src/config/bitcoin-config.h.in
 src/config/stamp-h1
+src/obj
 share/setup.nsi
 share/qt/Info.plist