Modernize dependency management

[amotl]

About

• Inline all requirements into setup.py
• Dissolve all requirements/* files
• Add Make target install-develop for installing the package in editable mode

[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (8a48c6d) 99.52% compared to head (7106f79) 99.52%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #67 +/- ## ======================================= Coverage 99.52% 99.52% ======================================= Files 18 18 Lines 425 425 ======================================= Hits 423 423 Misses 2 2 ``` | [Flag](https://app.codecov.io/gh/ip-tools/python-epo-ops-client/pull/67/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ip-tools) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/ip-tools/python-epo-ops-client/pull/67/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ip-tools) | `99.52% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ip-tools#carryforward-flags-in-the-pull-request-comment) to find out more.

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