fix and improve sql package

[alespour]

Branch: https://github.com/bonitoo-io/flux/tree/fix/sql-misc

Bugs:

• Snowflake: translationFunc - missing outgoing TUint mapping
• Snowflake: InitColumnTypes - only when scale == 0 then integer can be assumed
• MySQL: translationFunc: TUint should map to BIGINT UNSIGNED
• all: translationFunc: unsupported type error whould be reported with codes.Invalid instead of codes.Internal

Refactor:

• mysql, postgres, sqlite - map should be outside of translationFunc and not use String() just like in recently added db supports
• to.go: CreateInsertComponents() - getTranslationFunc() called in loop, label map not used anywhere

Enhancements:

• Azure: use new public API to get tokens, at least for MSI token
  • go.mod NOTE There already is a pending PR #3172 for Azure dep update
    • autorest: v0.11.4
    • adal: v0.9.2