move to multi-arch repos from leap 15.4 onwards

[phillxnet]

We are currently (testing branch) in the final stages of preparing our first "Build on openSUSE" Leap 15.4 rpms, after having faced significant difficulties regarding our prior (master branch) legacy build system which have now been mostly addressed by:
"Replace Buildout with Poetry #2432" #2434
along with numerous follow-up patches in testing branch to date.

It is thus proposed that we now move our existing x86_64 repo to be a multi-arch repository as per our upstream openSUSE repositories, and drop our prior aarch64 specific repositories. Clearing the way for easier additional architecture expansion in for example the "riscv64" i.e RISC V 64bit, along with easing multi-arch instructions. And hopefully some simplification in our architecture sensitive code: of which there is very little outside our repo concerns address in this issue.

Currently our rpm repositories have the following structure (repo db files omitted for simplicity):

leap
│   ├── 15.2
│   │   ├── repodata
│   │   └── rockstor-4.1.0-0.x86_64.rpm
│   ├── 15.2_aarch64
│   │   ├── repodata
│   │   └── rockstor-4.1.0-0.aarch64.rpm
│   ├── 15.3
│   │   ├── repodata
│   │   ├── rockstor-4.1.0-0.x86_64.rpm
│   │   └── rockstor-4.5.0-0.x86_64.rpm
│   └── 15.3_aarch64
│       ├── repodata
│       ├── rockstor-4.1.0-0.aarch64.rpm
│       └── rockstor-4.5.0-0.aarch64.rpm
└── tumbleweed
    ├── repodata
    └── rockstor-4.0.1-0.x86_64.rpm

Noting here that our Tumbleweed repo also suffered from a build system failure in our prior (in master branch) use of buildout. It is hoped that our recent move to Poetry in the above referenced pr will, in turn, allow us also to approach Tumbleweed releases also. Although we have Python 2 difficulties still outstanding.

The proposed multi-arch structure would be as follows:

leap
│   ├── 15.4
│   │   ├── x86_64
│   │       └── rockstor-4.5.4-0.x86_64.rpm
│   │   ├── aarch64
│   │       └── rockstor-4.5.4-0.aarch64.rpm
│   │   └── repodata
tumbleweed
    ├── x86_64
         └── rockstor-4.5.4-0.x86_64.rpm
    ├── aarch64
         └── rockstor-4.5.4-0.aarch64.rpm
    └── repodata

[phillxnet]

From this issues original text it can be seen that we began providing aarch64 repos from Leap 15.2 onwards.
As such, given we are only leaving all existing repositories as-is, we should for this issue modify the code so existing 15.2 and 15.3 hosted systems continue to use the existing single arch repositories. However given 15.3 is already EOL we are not likely to release many more updates for that Leap version. But the intention is to at least get folks over to the newer Poetry built rpms, if possible. It is also noteworthy that we no longer release rpms for Leap 15.2 so we are only really considering 15.3 onwards in this issue.

[phillxnet]

With the proposed in-development changes, to be submitted via linked pull request, we have:

Leap 15.3 before:

x86_64:

Rockstor-Testing    | Rockstor-Testing    | Yes     | (r ) Yes  | Yes     | http://updates.rockstor.com:8999/rockstor-testing/leap/15.3

aarch64:

Rockstor-Testing    | Rockstor-Testing    | Yes     | ( p) Yes  | Yes     | http://updates.rockstor.com:8999/rockstor-testing/leap/15.3_aarch64

Leap 15.3 after proposed change:

x86_64:

Rockstor-Testing    | Rockstor-Testing    | Yes     | (r ) Yes  | Yes     | http://updates.rockstor.com:8999/rockstor-testing/leap/15.3

aarch64:

Rockstor-Testing     | Rockstor-Testing   | Yes     | ( p) Yes  | Yes     | http://updates.rockstor.com:8999/rockstor-testing/leap/15.3_aarch64

So no change from 15.3 to 15.4 as intended.

Leap 15.4 after:

N.B. we haven't release a version before the proposed change) - MULTI-ARCH

x86_64:

Rockstor-Testing    | Rockstor-Testing    | Yes     | ( p) Yes  | Yes     | http://updates.rockstor.com:8999/rockstor-testing/leap/15.4

aarch64:

Rockstor-Testing    | Rockstor-Testing    | Yes     | ( p) Yes  | Yes     | http://updates.rockstor.com:8999/rockstor-testing/leap/15.4

[phillxnet]

Closing as fixed by:
#2462