Add four IBM i release repositories

[ThePrez]

Title 1

• IBM i 7.3 release repository

Title 2

• IBM i 7.4 release repository

Title 3

• IBM i 7.5 release repository

Title 4

• IBM i 7.6 release repository

Repository data location 1

• https://public.dhe.ibm.com/software/ibmi/products/pase/rpms/repo-7.3/repodata/repomd.xml

Repository data location 2

• https://public.dhe.ibm.com/software/ibmi/products/pase/rpms/repo-7.4/repodata/repomd.xml

Repository data location 3

• https://public.dhe.ibm.com/software/ibmi/products/pase/rpms/repo-7.5/repodata/repomd.xml

Repository data location 4

• https://public.dhe.ibm.com/software/ibmi/products/pase/rpms/repo-7.6/repodata/repomd.xml

Package links

• Installation: http://ibm.biz/ibmi-rpms
• IBM i open source documentation: http://ibm.biz/ibmi-oss-docs
• IBM i open source resources: http://ibm.biz/ibmioss

Additional details In addition to the repository at https://repology.org/repository/ibmi (needs updating per #1321), IBM also delivers a repository for every major release of IBM i. There are currently four live "release" repositories, corresponding to four IBM i releases.

Submitting as one issue as they are all intrinsically linked (and I assume this is easiest for the maintainers), but let me know if you prefer four separate issues.

Thanks!

[AMDmi3]

Same issue as in #1321

[ThePrez]

Can close this and I can resubmit when we sort out recipe distribution