chore(gnoclient): Add Run support

[jefft0]

gnoclient already has Call which does the same operation as gnokey maketx call. This PR adds Run to do the same thing as gnokey maketx run. It closely follows the implementation in gnokey.

(When this PR is merged, in Gno Native Kit we will add the thin wrapper for Run, similar to the wrapper for Call. We need this so that a command-line app can run a test script on the blockchain to, for example, stress test by adding hundreds of messages to r/demo/boards in a single call. It would be too slow to make hundreds of separate calls.)

To test, I called Run with the test script in this gist. As expected, the result is:

# HELLO WORLD!
## users.Render("")
 * [test_1](/r/demo/users:test_1)


## for i < 10 {print "hey hey hey!"}
0. hey hey hey!
1. hey hey hey!
2. hey hey hey!
3. hey hey hey!
4. hey hey hey!
5. hey hey hey!
6. hey hey hey!
7. hey hey hey!
8. hey hey hey!
9. hey hey hey!

## tests.* & std.*
- `tests.CurrentRealmPath` gno.land/r/demo/tests
- `tests.IsOriginCall` false
- `tests.GetPrevRealm` (struct{("g1a9r05e34s7dxe7wh8v00lnewnxtfnfq02gn5ws" std.Address),("gno.land/r/g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5/run" string)} std.Realm)
- `std.GetOrigCaller` g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5
- `std.PrevRealm` (struct{("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5" std.Address),("" string)} std.Realm)

## stateful check
- before: 0
- after: 10

## bf
source:  ++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.
result:  Hello World

## complex types
- before:  foobar
- after:  foobar_modified

[codecov]

Codecov Report

Attention: 15 lines in your changes are missing coverage. Please review.

Comparison is base (17b1303) 55.73% compared to head (e3b7c8a) 55.96%.
Report is 12 commits behind head on master.

Files	Patch %	Lines
gno.land/pkg/gnoclient/client_txs.go	67.39%	10 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1574      +/-   ##
==========================================
+ Coverage   55.73%   55.96%   +0.23%     
==========================================
  Files         435      435              
  Lines       65933    66742     +809     
==========================================
+ Hits        36748    37354     +606     
- Misses      26303    26465     +162     
- Partials     2882     2923      +41     

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[moul]

That looks good.

Can you add a unit test, or an integration one?
If needed, @gfanton can probably give you some hints.

[jefft0]

@moul, I added a test for Run. To keep the expected output small, it just uses one of the tests from the example gist. Is that right, or do you want the test script to be bigger? (This is testing the gnoclient Run method, not the back end VM support for Run.)