Remove json dependency

[BenediktBurger]

• Removes dependency on jsonrpc2-objects and jsonrpc2-pyclient.
  These two dependencies can be written in two small files, which enables us to support older versions of Python than the dependencies allow.
• Adds a small version of RPCServer for use in Python<3.9 instead of the version of openrpc package.
  This self written version does not yet support fully openrpc creation of method description, therefore it is good to keep openrpc as a dependency for those python versions, where it is available.

Closes #5

[codecov]

Codecov Report

Attention: Patch coverage is 93.10345% with 18 lines in your changes are missing coverage. Please review.

Project coverage is 87.63%. Comparing base (4cc7cca) to head (549f628).
Report is 2 commits behind head on main.

Files	Patch %	Lines
pyleco/json_utils/rpc_server_definition.py	84.81%	7 Missing and 5 partials ⚠️
pyleco/json_utils/errors.py	88.88%	4 Missing ⚠️
pyleco/coordinators/coordinator.py	84.61%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #63      +/-   ##
==========================================
+ Coverage   87.28%   87.63%   +0.35%     
==========================================
  Files          33       36       +3     
  Lines        2626     2846     +220     
  Branches      314      343      +29     
==========================================
+ Hits         2292     2494     +202     
- Misses        280      293      +13     
- Partials       54       59       +5     

Flag	Coverage Δ
unittests	87.63% <93.10%> (+0.35%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[BenediktBurger]

Working for a week in the lab.

[bilderbuchi]

• Removes dependency on jsonrpc2-objects and jsonrpc2-pyclient.
  These two dependencies can be written in two small files, which enables us to support older versions of Python than the dependencies allow.

  • Adds a small version of RPCServer for use in Python<3.9 instead of the version of openrpc package.
    This self written version does not yet support fully openrpc creation of method description, therefore it is good to keep openrpc as a dependency for those python versions, where it is available.

Closes #5

A few thoughts from skimming the PR:

• I would caution against supporting py37, as it has been EOL since last year. Py38 follows this year.
• The package metadata has requires-python = ">=3.9", so installation should not be possible on lower Python versions anyway. I guess you need py38, nevertheless?
• It's good that you restricted the self-written code to just use it when necessary, as it's easier to remove later, and reduce maintenance burden.

[BenediktBurger]

Thanks for your comments

* I would caution against supporting py37, as it has been EOL since last year. Py38 follows this year.

The idea was, to include pyleco into pymodaq, which supports python 3.8 and @seb5g mentioned, that he would like to use it on an old system, which only allows python 3.7. However, I noticed, that python 3.7 is not achievable in #61 , so I dropped that idea.

* The package metadata has `requires-python = ">=3.9"`, so installation should not be possible on lower Python versions anyway. I guess you need py38, nevertheless?

This PR is the first one of two, which adds objects. The second one (#64 ) with more changes, changes also that requirement.

* It's good that you restricted the self-written code to just use it when necessary, as it's easier to remove later, and reduce maintenance burden.

Especially as it is not as complete as the imported code.