For normal alpha/release builds, we use the date from the commit, on
which we add the numbers from the version string as seconds (in order to
keep increasing the build date when we release a new version without
adding new commits).

For nightly-testbuild, we use the date from the commit.

For nightly we try to parse the day from the version number, or use the
current day at 00:00:01.

Bug 40889: Add mullvad sha256sums URL to download-unsigned-sha256sums-gpg-signatures-from-people-tpo

In #40871 I incorrectly set `keyring/boklm.gpg` in format `GPG keybox
database version 1`, instead of `PGP/GPG key public ring (v4)`.

This was fixed with:

 gpg --no-default-keyring --keyring ./keyring/boklm.gpg --export > ./keyring/boklm-2.gpg
 mv ./keyring/boklm-2.gpg ./keyring/boklm.gpg

Add some missing spaces that make GitLab not understand the markup
correctly.

Some version numbers like 12.5 can be stored as a numeric value instead
of a string, so we should explicitely store the version as a string. At
the same time we do the same for tag/git_tag (although tags are less
likely to look like a number).

- migrated Docs-PB to Docs-MB in browser project
- updated browser build script to take new path into account
- created separate ChangeLog-MB.txt softlink, migrate ChangeLog.txt softlink
  to ChangeLog-TBB.txt
- updated changelog-format-blog-post script to reference correct file and
  fix bug in raw changelog link

Add the commit hash and GitLab URL to the mozconfig to make them appear
in about:buildconfig on Android, too.

HFS has the disadvantage that we cannot grow the filesystem while
adding files.
We have to estimate an initial size, instead, and we relied on du for
this. However, du depends on the underlying filesystem, and this could
lead to reproducibility issues (because the HFS headers tell different
sizes).

So, with this change, we compute a rough number of needed blocks by
taking the actual size of the files.

Overshooting is not a problem, because DMG is compressed with bzip2, so
unused space will be trimmed, eventually.

This reverts commit 40298e79.

To avoid broken nightly builds, we set obfs4 nightly to a fixed commit,
until the changes required by the renaming from obfs4 to lyrebird are
done.

Bug 40870: Remove URL without browser name from signing/download-unsigned-sha256sums-gpg-signatures-from-people-tpo

This is the first alpha of the 12.5 series.

We can use the same GitLab token we use to create the changelogs also
to download the list of jobs in the manual project, and a new CI
artifact if needed.

In 076ffcf1 we stopped using the main
branch, because the build of tpo/anti-censorship/pluggable-transports/obfs4#40011.
Since this is now fixed, we can use the main branch again.

The Go compiler is written in Go, but it is possible to bootstrap it
from C wiht Go 1.4.
Before this commit, we used to build Go 1.4 for all our platforms,
so we built a compiler to throw it away several times.

Starting from Go 1.20, the team decided to require Go V-3 to bootstrap
(i.e., Go 1.17 to bootrastrap Go 1.20).
Bootstrapping is still feasible, but throwing away two compilers is
not a good idea. So, we decided to create a Go bootstrap project, and
build it only once (for Linux amd64) until it will be able to build
more recent Go compilers.