fix: show error about balance if there is no balance

[nikonov1101]

No description provided.

[antmat]

I'm not really familiar with the code, but:

• orderLoop is very big for understanding
• you iterate via orders, but if there is no balance for the FIRST order you break the loop. Looks like improper behaviour.
  I might be wrong, but please add some explanation for this PR

[nikonov1101]

@antmat You are right about the first item, that breaks the loop, thanks!

filter orders by balance and allowance to prevent dealing with too expensive orders is added.

[codecov-io]

Codecov Report

Merging #398 into master will increase coverage by 0.26%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #398      +/-   ##
==========================================
+ Coverage   18.18%   18.45%   +0.26%     
==========================================
  Files          88       90       +2     
  Lines        9459     9560     +101     
==========================================
+ Hits         1720     1764      +44     
- Misses       7554     7608      +54     
- Partials      185      188       +3

Impacted Files	Coverage Δ
insonmnia/node/market.go	66.47% <100%> (+1.41%)	⬆️
fusrodah/hub/server.go	44.11% <0%> (ø)
fusrodah/miner/server.go	28.3% <0%> (ø)

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[antmat]

Still orderLoop is very hard to understand, but this paerticular PR is clear and LGTM