refactor: Change sortNode to orderNode.

[shahzadlone]

Relevant issue(s)

Resolves #590

Description

Changes sortNode to orderNode, and some file names and other instances for consistency.

Tasks

• I made sure the code is well commented, particularly hard-to-understand areas.
• I made sure the repository-held documentation is changed accordingly.
• I made sure the pull request title adheres to the conventional commit style (the subset used in the project can be found in tools/configs/chglog/config.yml).
• I made sure to discuss its limitations such as threats to validity, vulnerability to mistake and misuse, robustness to invalidation of assumptions, resource requirements, ...

How has this been tested?

make test & CI

Specify the platform(s) on which this was tested:

• Manjaro WSL2

[codecov]

Codecov Report

Merging #591 (a4be02f) into develop (0f54d22) will not change coverage.
The diff coverage is 87.50%.

❗ Current head a4be02f differs from pull request most recent head 2cc94b1. Consider uploading reports for the commit 2cc94b1 to get more accurate results

@@           Coverage Diff            @@
##           develop     #591   +/-   ##
========================================
  Coverage    56.17%   56.17%           
========================================
  Files          121      121           
  Lines        14276    14276           
========================================
  Hits          8020     8020           
  Misses        5557     5557           
  Partials       699      699           

Impacted Files	Coverage Δ
db/container/container.go	84.61% <ø> (ø)
query/graphql/planner/explain.go	63.79% <ø> (ø)
query/graphql/planner/order.go	83.50% <80.95%> (ø)
query/graphql/parser/filter.go	62.06% <88.88%> (ø)
query/graphql/parser/query.go	80.18% <100.00%> (ø)
query/graphql/planner/planner.go	73.58% <100.00%> (ø)
query/graphql/planner/select.go	75.00% <100.00%> (ø)

[fredcarle]

LGTM. Just a small non-blocking suggestion.