[TT-1190] support multiple configuration names

[Tofel]

Adds the following change:

config, err = tc.GetConfig([]string{"A", "B", "C"}, tc.VRFv2Plus)
require.NoError(t, err, "Error getting config")

which means that in this case the overriding order would be:

• configuration without any name
• "A" configuration
• "B" configuration
• "C" configuration

If config had this structure:

struct Config type {
     Text_1 string `toml:"text_1"`
     Text_2 string `toml:"text_2"`
     Text_3 string `toml:"text_3"`
     Text_4 string `toml:"text_4"`
}

and if TOML looked like this:

text_1 = "first"
text_2 = "second"
text_3 = "third"
text_4 = "original"

[A]
text_1 = "overwritten_from_A"

[B]
text_2 = "overwritten_from_B"

[C]
text_3 = "overwritten_from_C"

The result would be:

text_1 = "overwritten_from_A"
text_2 = "overwritten_from_B*"
text_3 = "overwritten_from_C"
text_4 = "original"

[Tofel]

needs OK from @iljapavlovs before merging

[gheorghestrimtu]

[]string ftw

[cl-sonarqube-production]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

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