fix: transpile step

[tbruyelle]

The gno transpile -gobuild command did not work because there was no go.mod file in the directory. Adding the GO111MODULE=off env discards this error and makes the command work properly.

Other changes:

• Removed the GnoFile argument from Transpile because the command should be run on the workspace folder instead of just the directory of where the GnoFile is located. Adding a new field workspaceFolder in the server struct for that purpose, this field is set at the initialize LSP step.
• Merge the Transpile() and TranspileAndBuild() functions, because the errors format between transpile and gobuild is the same since fix: unify the precompile output to make it easier to parse and read.  gno#1670.
• Update ParseErrors so it stops trying the guess the column end of the error (remove call to findErrors). I consider this step unecessary because it is not reliable. This also makes the function faster because it stops iterating over the file's tokens.
• Improve error handling so the absence of gno binary is reported.
• Update getTranspileDiagnostics() so it filters the errors according to the file in parameter. Also removes looking at the errors in the typecheck cache, because all the errors are returned by gno transpile -gobuild. I'm not sure about the future of typecheck cache with this change, maybe it should be completely removed.

As a result of these changes, the test document_open.txtar is updated:

• the error code is now transpile instead of typecheck (because the errors come now from the transpile command instead of the typecheck cache)
• the column end is set to column start (because the transpile command only returns the start column and findErrors is no longer invoked)

I know these changes are a bit opinionated, I am of course open to discussion.