Improve organization of release assets

[chaoticbob]

Header Files
Can the header files that's located in the root of all the release asset zip and tar.gz files be moved into an include or inc or maybe even a include/slang or inc/slang? There's not a strong technical argument for this but for project setups this makes it more obvious what the path entry is doing.

Binaries
Currently, the binaries are located a few directories down from the root itself: bin/<platform>/release/[slangc, *.so, *.dll]. Is possible to trim down a bit? Since the release assets already have the platform name, can the binary content just be in bin directory?

[bmillsNV]

if we make a change - some concerns about backwards compatibility. Maybe just put in the release notes? @ArielG-NV to propose something, then we can get alignment and move forward in the next sprint.

[expipiplus1]

This should be fixed by #3703

[ArielG-NV]

if we make a change - some concerns about backwards compatibility. Maybe just put in the release notes? @ArielG-NV to propose something, then we can get alignment and move forward in the next sprint.

Seeing what @expipiplus1 said

This should be fixed by #3703

It seems this task is already being handled by @expipiplus1?