CI: Run all tests when coverage is enabled ...

A recent change in the CI enabled coverage, however it did so on
the latest tags, meaning we were no longer running the other
tests (from the testsuite). This corrects it.

Add a CI step to upload assets on release creation ...

We haven't had assets generated for releases since v1.29.0,
however some external code depend on them (dlang-community/setup-dlang, namely).
This will fix it and make it less likely to be forgotten in the future.

Build the tests and binary with -cov on POSIX ...

The CI was sending empty coverage reports because nothing
was being generated, as the variable was always false.
In the process, a bit of dead code was removed.

CI: Move single checks to Github, remove dead code ...

Remove support for very old frontend - we were not testing it anyways.
Move the useful checks to another job so they run once.

Remove internal mentions to Travis

add pr_info GitHub actions run ...

Gives summary about some basic statistics, deprecations and warnings

Revert "Remove Vibe.d HTTP support / library-nonet" ...

This reverts commit db49cbe.

Remove Vibe.d HTTP support / library-nonet ...

library-nonet has been broken for years, and is not used.
Most importantly, it has no support for timeout.
Lastly, the likely reason it was originally introduced was to
avoid a hard dependency on cURL, something that has been fixed
in Phobos directly.

Remove a few usages of old version-spec approach from test-suite

Add configy library, dyaml, tinyendian ...

Versions are:
- tinyendian v0.2.0
- dyaml v0.9.0
- Configy commit 361ca47 + PR34

vendor

Attempt to replace run-unittest.sh by run-unittest.d. Inception

ci: use GNU tar when using darwin platform ...

Signed-off-by: Luís Ferreira <contact@lsferreira.net>

ci: build release .tar.gz without travis owner and group id ...

Signed-off-by: Luís Ferreira <contact@lsferreira.net>

Update supported compiler versions ...

Update LDC used for release from v1.20 to v1.22,
move coverage target to be the latest compiler
(so hopefully the less buggy too),
and make sure we only support the last 10 releases.

Travis,deploy: Update list of supported compilers ...

Build with the latest LDC, which doesn't have the stack overflow in GC bug.

Move most CI scripts in scripts/ci ...

The root directory was getting a bit crowded.
semaphore-ci.sh was not moved, because there's no visible way to configure semaphore from the repository.
Additionally, build.d is left in the root directory as it's useful to have it here,
and it'll be only one script one build.sh, build.cmd, and build-gdc.sh are gone.