Allow to disable reload timer

[bjoernricks]

Add a function that handles setting the default reload interval to less
or equal to 0 to disable the reloading of entities. Update load and
getReloadInterval methods to stop loading if the calculated reload
interval is less or equal to 0.

Checklist:

• [n/a] Tests
• CHANGELOG Entry

[codecov]

Codecov Report

Merging #1619 into master will decrease coverage by <.01%.
The diff coverage is 46.42%.

@@            Coverage Diff             @@
##           master    #1619      +/-   ##
==========================================
- Coverage   41.91%   41.91%   -0.01%     
==========================================
  Files        1044     1044              
  Lines       23928    23939      +11     
  Branches     6610     6612       +2     
==========================================
+ Hits        10030    10034       +4     
- Misses      12652    12659       +7     
  Partials     1246     1246

Impacted Files	Coverage Δ
gsa/src/web/pages/reports/detailspage.js	3.5% <16.66%> (+0.35%)	⬆️
gsa/src/web/entities/container.js	41.46% <66.66%> (-0.3%)	⬇️
gsa/src/web/entity/container.js	81.81% <70%> (-3.19%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cf79a4a...f5254dc. Read the comment docs.